Merge tag 'trace-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "The biggest change for this release is in the histogram code:

   - Add "onchange(var)" histogram handler that executes a action when
     $var changes.

   - Add new "snapshot()" action for histogram handlers, that causes a
     snapshot of the ring buffer when triggered. ie.
     onchange(var).snapshot() will trigger a snapshot if var changes.

   - Add alternative for "trace()" action. Currently, to trigger a
     synthetic event, the name of that event is used as the handler
     name, which is inconsistent with the other actions.
     onchange(var).synthetic(param) where it can now be
     onchange(var).trace(synthetic, param). The older method will still
     be allowed, as long as the synthetic events do not overlap with
     other handler names.

   - The histogram documentation at testcases were updated for the new
     changes.

  Outside of the histogram code, we have:

   - Added a quicker way to enable set_ftrace_filter files, that will
     make it much quicker to bisect tracing a function that shouldn't be
     traced and crashes the kernel. (You can echo in numbers to
     set_ftrace_filter, and it will select the corresponding function
     that is in available_filter_functions).

   - Some better displaying of the tracing data (and more information
     was added).

  The rest are small fixes and more clean ups to the code"

* tag 'trace-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (37 commits)
  tracing: Use strncpy instead of memcpy when copying comm in trace.c
  tracing: Use strncpy instead of memcpy when copying comm for hist triggers
  tracing: Use strncpy instead of memcpy for string keys in hist triggers
  tracing: Use str_has_prefix() in synth_event_create()
  x86/ftrace: Fix warning and considate ftrace_jmp_replace() and ftrace_call_replace()
  tracing/perf: Use strndup_user() instead of buggy open-coded version
  doc: trace: Fix documentation for uprobe_profile
  tracing: Fix spelling mistake: "analagous" -> "analogous"
  tracing: Comment why cond_snapshot is checked outside of max_lock protection
  tracing: Add hist trigger action 'expected fail' test case
  tracing: Add alternative synthetic event trace action test case
  tracing: Add hist trigger onchange() handler test case
  tracing: Add hist trigger snapshot() action test case
  tracing: Add SPDX license GPL-2.0 license identifier to inter-event testcases
  tracing: Add alternative synthetic event trace action syntax
  tracing: Add hist trigger onchange() handler Documentation
  tracing: Add hist trigger onchange() handler
  tracing: Add hist trigger snapshot() action Documentation
  tracing: Add hist trigger snapshot() action
  tracing: Add conditional snapshot
  ...

30 files changed, 1695 insertions, 420 deletions

diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 0131df7f5968..7c5e6d6ab5d1 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -233,6 +233,12 @@ of ftrace. Here is a list of some of the key files:
 	This interface also allows for commands to be used. See the
 	"Filter commands" section for more details.
 
+	As a speed up, since processing strings can't be quite expensive
+	and requires a check of all functions registered to tracing, instead
+	an index can be written into this file. A number (starting with "1")
+	written will instead select the same corresponding at the line position
+	of the "available_filter_functions" file.
+
   set_ftrace_notrace:
 
 	This has an effect opposite to that of
@@ -1396,6 +1402,57 @@ enabling function tracing, we incur an added overhead. This
 overhead may extend the latency times. But nevertheless, this
 trace has provided some very helpful debugging information.
 
+If we prefer function graph output instead of function, we can set
+display-graph option::
+ with echo 1 > options/display-graph
+
+  # tracer: irqsoff
+  #
+  # irqsoff latency trace v1.1.5 on 4.20.0-rc6+
+  # --------------------------------------------------------------------
+  # latency: 3751 us, #274/274, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4)
+  #    -----------------
+  #    | task: bash-1507 (uid:0 nice:0 policy:0 rt_prio:0)
+  #    -----------------
+  #  => started at: free_debug_processing
+  #  => ended at:   return_to_handler
+  #
+  #
+  #                                       _-----=> irqs-off
+  #                                      / _----=> need-resched
+  #                                     | / _---=> hardirq/softirq
+  #                                     || / _--=> preempt-depth
+  #                                     ||| /
+  #   REL TIME      CPU  TASK/PID       ||||     DURATION                  FUNCTION CALLS
+  #      |          |     |    |        ||||      |   |                     |   |   |   |
+          0 us |   0)   bash-1507    |  d... |   0.000 us    |  _raw_spin_lock_irqsave();
+          0 us |   0)   bash-1507    |  d..1 |   0.378 us    |    do_raw_spin_trylock();
+          1 us |   0)   bash-1507    |  d..2 |               |    set_track() {
+          2 us |   0)   bash-1507    |  d..2 |               |      save_stack_trace() {
+          2 us |   0)   bash-1507    |  d..2 |               |        __save_stack_trace() {
+          3 us |   0)   bash-1507    |  d..2 |               |          __unwind_start() {
+          3 us |   0)   bash-1507    |  d..2 |               |            get_stack_info() {
+          3 us |   0)   bash-1507    |  d..2 |   0.351 us    |              in_task_stack();
+          4 us |   0)   bash-1507    |  d..2 |   1.107 us    |            }
+  [...]
+       3750 us |   0)   bash-1507    |  d..1 |   0.516 us    |      do_raw_spin_unlock();
+       3750 us |   0)   bash-1507    |  d..1 |   0.000 us    |  _raw_spin_unlock_irqrestore();
+       3764 us |   0)   bash-1507    |  d..1 |   0.000 us    |  tracer_hardirqs_on();
+      bash-1507    0d..1 3792us : <stack trace>
+   => free_debug_processing
+   => __slab_free
+   => kmem_cache_free
+   => vm_area_free
+   => remove_vma
+   => exit_mmap
+   => mmput
+   => flush_old_exec
+   => load_elf_binary
+   => search_binary_handler
+   => __do_execve_file.isra.32
+   => __x64_sys_execve
+   => do_syscall_64
+   => entry_SYSCALL_64_after_hwframe
 
 preemptoff
 ----------
@@ -2784,6 +2841,38 @@ Produces::
 
 We can see that there's no more lock or preempt tracing.
 
+Selecting function filters via index
+------------------------------------
+
+Because processing of strings is expensive (the address of the function
+needs to be looked up before comparing to the string being passed in),
+an index can be used as well to enable functions. This is useful in the
+case of setting thousands of specific functions at a time. By passing
+in a list of numbers, no string processing will occur. Instead, the function
+at the specific location in the internal array (which corresponds to the
+functions in the "available_filter_functions" file), is selected.
+
+::
+
+  # echo 1 > set_ftrace_filter
+
+Will select the first function listed in "available_filter_functions"
+
+::
+
+  # head -1 available_filter_functions
+  trace_initcall_finish_cb
+
+  # cat set_ftrace_filter
+  trace_initcall_finish_cb
+
+  # head -50 available_filter_functions | tail -1
+  x86_pmu_commit_txn
+
+  # echo 1 50 > set_ftrace_filter
+  # cat set_ftrace_filter
+  trace_initcall_finish_cb
+  x86_pmu_commit_txn
 
 Dynamic ftrace with the function graph tracer
 ---------------------------------------------
diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
index 7dda76503127..0ea59d45aef1 100644
--- a/Documentation/trace/histogram.rst
+++ b/Documentation/trace/histogram.rst
@@ -25,7 +25,7 @@ Documentation written by Tom Zanussi
 
         hist:keys=<field1[,field2,...]>[:values=<field1[,field2,...]>]
           [:sort=<field1[,field2,...]>][:size=#entries][:pause][:continue]
-          [:clear][:name=histname1] [if <filter>]
+          [:clear][:name=histname1][:<handler>.<action>] [if <filter>]
 
   When a matching event is hit, an entry is added to a hash table
   using the key(s) and value(s) named.  Keys and values correspond to
@@ -1831,41 +1831,87 @@ and looks and behaves just like any other event::
 Like any other event, once a histogram is enabled for the event, the
 output can be displayed by reading the event's 'hist' file.
 
-2.2.3 Hist trigger 'actions'
-----------------------------
+2.2.3 Hist trigger 'handlers' and 'actions'
+-------------------------------------------
 
-A hist trigger 'action' is a function that's executed whenever a
-histogram entry is added or updated.
+A hist trigger 'action' is a function that's executed (in most cases
+conditionally) whenever a histogram entry is added or updated.
 
-The default 'action' if no special function is explicitly specified is
-as it always has been, to simply update the set of values associated
-with an entry.  Some applications, however, may want to perform
-additional actions at that point, such as generate another event, or
-compare and save a maximum.
+When a histogram entry is added or updated, a hist trigger 'handler'
+is what decides whether the corresponding action is actually invoked
+or not.
 
-The following additional actions are available.  To specify an action
-for a given event, simply specify the action between colons in the
-hist trigger specification.
+Hist trigger handlers and actions are paired together in the general
+form:
 
-  - onmatch(matching.event).<synthetic_event_name>(param list)
+  <handler>.<action>
 
-    The 'onmatch(matching.event).<synthetic_event_name>(params)' hist
-    trigger action is invoked whenever an event matches and the
-    histogram entry would be added or updated.  It causes the named
-    synthetic event to be generated with the values given in the
+To specify a handler.action pair for a given event, simply specify
+that handler.action pair between colons in the hist trigger
+specification.
+
+In theory, any handler can be combined with any action, but in
+practice, not every handler.action combination is currently supported;
+if a given handler.action combination isn't supported, the hist
+trigger will fail with -EINVAL;
+
+The default 'handler.action' if none is explicity specified is as it
+always has been, to simply update the set of values associated with an
+entry.  Some applications, however, may want to perform additional
+actions at that point, such as generate another event, or compare and
+save a maximum.
+
+The supported handlers and actions are listed below, and each is
+described in more detail in the following paragraphs, in the context
+of descriptions of some common and useful handler.action combinations.
+
+The available handlers are:
+
+  - onmatch(matching.event)    - invoke action on any addition or update
+  - onmax(var)                 - invoke action if var exceeds current max
+  - onchange(var)              - invoke action if var changes
+
+The available actions are:
+
+  - trace(<synthetic_event_name>,param list)   - generate synthetic event
+  - save(field,...)                            - save current event fields
+  - snapshot()                                 - snapshot the trace buffer
+
+The following commonly-used handler.action pairs are available:
+
+  - onmatch(matching.event).trace(<synthetic_event_name>,param list)
+
+    The 'onmatch(matching.event).trace(<synthetic_event_name>,param
+    list)' hist trigger action is invoked whenever an event matches
+    and the histogram entry would be added or updated.  It causes the
+    named synthetic event to be generated with the values given in the
     'param list'.  The result is the generation of a synthetic event
     that consists of the values contained in those variables at the
-    time the invoking event was hit.
-
-    The 'param list' consists of one or more parameters which may be
-    either variables or fields defined on either the 'matching.event'
-    or the target event.  The variables or fields specified in the
-    param list may be either fully-qualified or unqualified.  If a
-    variable is specified as unqualified, it must be unique between
-    the two events.  A field name used as a param can be unqualified
-    if it refers to the target event, but must be fully qualified if
-    it refers to the matching event.  A fully-qualified name is of the
-    form 'system.event_name.$var_name' or 'system.event_name.field'.
+    time the invoking event was hit.  For example, if the synthetic
+    event name is 'wakeup_latency', a wakeup_latency event is
+    generated using onmatch(event).trace(wakeup_latency,arg1,arg2).
+
+    There is also an equivalent alternative form available for
+    generating synthetic events.  In this form, the synthetic event
+    name is used as if it were a function name.  For example, using
+    the 'wakeup_latency' synthetic event name again, the
+    wakeup_latency event would be generated by invoking it as if it
+    were a function call, with the event field values passed in as
+    arguments: onmatch(event).wakeup_latency(arg1,arg2).  The syntax
+    for this form is:
+
+      onmatch(matching.event).<synthetic_event_name>(param list)
+
+    In either case, the 'param list' consists of one or more
+    parameters which may be either variables or fields defined on
+    either the 'matching.event' or the target event.  The variables or
+    fields specified in the param list may be either fully-qualified
+    or unqualified.  If a variable is specified as unqualified, it
+    must be unique between the two events.  A field name used as a
+    param can be unqualified if it refers to the target event, but
+    must be fully qualified if it refers to the matching event.  A
+    fully-qualified name is of the form 'system.event_name.$var_name'
+    or 'system.event_name.field'.
 
     The 'matching.event' specification is simply the fully qualified
     event name of the event that matches the target event for the
@@ -1896,6 +1942,12 @@ hist trigger specification.
               wakeup_new_test($testpid) if comm=="cyclictest"' >> \
               /sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger
 
+    Or, equivalently, using the 'trace' keyword syntax:
+
+    # echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\
+            trace(wakeup_new_test,$testpid) if comm=="cyclictest"' >> \
+            /sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger
+
     Creating and displaying a histogram based on those events is now
     just a matter of using the fields and new synthetic event in the
     tracing/events/synthetic directory, as usual::
@@ -2000,6 +2052,212 @@ hist trigger specification.
             Entries: 2
             Dropped: 0
 
+  - onmax(var).snapshot()
+
+    The 'onmax(var).snapshot()' hist trigger action is invoked
+    whenever the value of 'var' associated with a histogram entry
+    exceeds the current maximum contained in that variable.
+
+    The end result is that a global snapshot of the trace buffer will
+    be saved in the tracing/snapshot file if 'var' exceeds the current
+    maximum for any hist trigger entry.
+
+    Note that in this case the maximum is a global maximum for the
+    current trace instance, which is the maximum across all buckets of
+    the histogram.  The key of the specific trace event that caused
+    the global maximum and the global maximum itself are displayed,
+    along with a message stating that a snapshot has been taken and
+    where to find it.  The user can use the key information displayed
+    to locate the corresponding bucket in the histogram for even more
+    detail.
+
+    As an example the below defines a couple of hist triggers, one for
+    sched_waking and another for sched_switch, keyed on pid.  Whenever
+    a sched_waking event occurs, the timestamp is saved in the entry
+    corresponding to the current pid, and when the scheduler switches
+    back to that pid, the timestamp difference is calculated.  If the
+    resulting latency, stored in wakeup_lat, exceeds the current
+    maximum latency, a snapshot is taken.  As part of the setup, all
+    the scheduler events are also enabled, which are the events that
+    will show up in the snapshot when it is taken at some point:
+
+    # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
+
+    # echo 'hist:keys=pid:ts0=common_timestamp.usecs \
+            if comm=="cyclictest"' >> \
+            /sys/kernel/debug/tracing/events/sched/sched_waking/trigger
+
+    # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
+            onmax($wakeup_lat).save(next_prio,next_comm,prev_pid,prev_prio, \
+	    prev_comm):onmax($wakeup_lat).snapshot() \
+	    if next_comm=="cyclictest"' >> \
+	    /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
+
+    When the histogram is displayed, for each bucket the max value
+    and the saved values corresponding to the max are displayed
+    following the rest of the fields.
+
+    If a snaphot was taken, there is also a message indicating that,
+    along with the value and event that triggered the global maximum:
+
+    # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
+      { next_pid:       2101 } hitcount:        200
+	max:         52  next_prio:        120  next_comm: cyclictest \
+        prev_pid:          0  prev_prio:        120  prev_comm: swapper/6
+
+      { next_pid:       2103 } hitcount:       1326
+	max:        572  next_prio:         19  next_comm: cyclictest \
+        prev_pid:          0  prev_prio:        120  prev_comm: swapper/1
+
+      { next_pid:       2102 } hitcount:       1982 \
+	max:         74  next_prio:         19  next_comm: cyclictest \
+        prev_pid:          0  prev_prio:        120  prev_comm: swapper/5
+
+    Snapshot taken (see tracing/snapshot).  Details:
+	triggering value { onmax($wakeup_lat) }:        572	\
+	triggered by event with key: { next_pid:       2103 }
+
+    Totals:
+        Hits: 3508
+        Entries: 3
+        Dropped: 0
+
+    In the above case, the event that triggered the global maximum has
+    the key with next_pid == 2103.  If you look at the bucket that has
+    2103 as the key, you'll find the additional values save()'d along
+    with the local maximum for that bucket, which should be the same
+    as the global maximum (since that was the same value that
+    triggered the global snapshot).
+
+    And finally, looking at the snapshot data should show at or near
+    the end the event that triggered the snapshot (in this case you
+    can verify the timestamps between the sched_waking and
+    sched_switch events, which should match the time displayed in the
+    global maximum):
+
+    # cat /sys/kernel/debug/tracing/snapshot
+
+     <...>-2103  [005] d..3   309.873125: sched_switch: prev_comm=cyclictest prev_pid=2103 prev_prio=19 prev_state=D ==> next_comm=swapper/5 next_pid=0 next_prio=120
+     <idle>-0     [005] d.h3   309.873611: sched_waking: comm=cyclictest pid=2102 prio=19 target_cpu=005
+     <idle>-0     [005] dNh4   309.873613: sched_wakeup: comm=cyclictest pid=2102 prio=19 target_cpu=005
+     <idle>-0     [005] d..3   309.873616: sched_switch: prev_comm=swapper/5 prev_pid=0 prev_prio=120 prev_state=S ==> next_comm=cyclictest next_pid=2102 next_prio=19
+     <...>-2102  [005] d..3   309.873625: sched_switch: prev_comm=cyclictest prev_pid=2102 prev_prio=19 prev_state=D ==> next_comm=swapper/5 next_pid=0 next_prio=120
+     <idle>-0     [005] d.h3   309.874624: sched_waking: comm=cyclictest pid=2102 prio=19 target_cpu=005
+     <idle>-0     [005] dNh4   309.874626: sched_wakeup: comm=cyclictest pid=2102 prio=19 target_cpu=005
+     <idle>-0     [005] dNh3   309.874628: sched_waking: comm=cyclictest pid=2103 prio=19 target_cpu=005
+     <idle>-0     [005] dNh4   309.874630: sched_wakeup: comm=cyclictest pid=2103 prio=19 target_cpu=005
+     <idle>-0     [005] d..3   309.874633: sched_switch: prev_comm=swapper/5 prev_pid=0 prev_prio=120 prev_state=S ==> next_comm=cyclictest next_pid=2102 next_prio=19
+     <idle>-0     [004] d.h3   309.874757: sched_waking: comm=gnome-terminal- pid=1699 prio=120 target_cpu=004
+     <idle>-0     [004] dNh4   309.874762: sched_wakeup: comm=gnome-terminal- pid=1699 prio=120 target_cpu=004
+     <idle>-0     [004] d..3   309.874766: sched_switch: prev_comm=swapper/4 prev_pid=0 prev_prio=120 prev_state=S ==> next_comm=gnome-terminal- next_pid=1699 next_prio=120
+ gnome-terminal--1699  [004] d.h2   309.874941: sched_stat_runtime: comm=gnome-terminal- pid=1699 runtime=180706 [ns] vruntime=1126870572 [ns]
+     <idle>-0     [003] d.s4   309.874956: sched_waking: comm=rcu_sched pid=9 prio=120 target_cpu=007
+     <idle>-0     [003] d.s5   309.874960: sched_wake_idle_without_ipi: cpu=7
+     <idle>-0     [003] d.s5   309.874961: sched_wakeup: comm=rcu_sched pid=9 prio=120 target_cpu=007
+     <idle>-0     [007] d..3   309.874963: sched_switch: prev_comm=swapper/7 prev_pid=0 prev_prio=120 prev_state=S ==> next_comm=rcu_sched next_pid=9 next_prio=120
+  rcu_sched-9     [007] d..3   309.874973: sched_stat_runtime: comm=rcu_sched pid=9 runtime=13646 [ns] vruntime=22531430286 [ns]
+  rcu_sched-9     [007] d..3   309.874978: sched_switch: prev_comm=rcu_sched prev_pid=9 prev_prio=120 prev_state=R+ ==> next_comm=swapper/7 next_pid=0 next_prio=120
+      <...>-2102  [005] d..4   309.874994: sched_migrate_task: comm=cyclictest pid=2103 prio=19 orig_cpu=5 dest_cpu=1
+      <...>-2102  [005] d..4   309.875185: sched_wake_idle_without_ipi: cpu=1
+     <idle>-0     [001] d..3   309.875200: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=S ==> next_comm=cyclictest next_pid=2103 next_prio=19
+
+  - onchange(var).save(field,..	.)
+
+    The 'onchange(var).save(field,...)' hist trigger action is invoked
+    whenever the value of 'var' associated with a histogram entry
+    changes.
+
+    The end result is that the trace event fields specified as the
+    onchange.save() params will be saved if 'var' changes for that
+    hist trigger entry.  This allows context from the event that
+    changed the value to be saved for later reference.  When the
+    histogram is displayed, additional fields displaying the saved
+    values will be printed.
+
+  - onchange(var).snapshot()
+
+    The 'onchange(var).snapshot()' hist trigger action is invoked
+    whenever the value of 'var' associated with a histogram entry
+    changes.
+
+    The end result is that a global snapshot of the trace buffer will
+    be saved in the tracing/snapshot file if 'var' changes for any
+    hist trigger entry.
+
+    Note that in this case the changed value is a global variable
+    associated withe current trace instance.  The key of the specific
+    trace event that caused the value to change and the global value
+    itself are displayed, along with a message stating that a snapshot
+    has been taken and where to find it.  The user can use the key
+    information displayed to locate the corresponding bucket in the
+    histogram for even more detail.
+
+    As an example the below defines a hist trigger on the tcp_probe
+    event, keyed on dport.  Whenever a tcp_probe event occurs, the
+    cwnd field is checked against the current value stored in the
+    $cwnd variable.  If the value has changed, a snapshot is taken.
+    As part of the setup, all the scheduler and tcp events are also
+    enabled, which are the events that will show up in the snapshot
+    when it is taken at some point:
+
+    # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
+    # echo 1 > /sys/kernel/debug/tracing/events/tcp/enable
+
+    # echo 'hist:keys=dport:cwnd=snd_cwnd: \
+            onchange($cwnd).save(snd_wnd,srtt,rcv_wnd): \
+	    onchange($cwnd).snapshot()' >> \
+	    /sys/kernel/debug/tracing/events/tcp/tcp_probe/trigger
+
+    When the histogram is displayed, for each bucket the tracked value
+    and the saved values corresponding to that value are displayed
+    following the rest of the fields.
+
+    If a snaphot was taken, there is also a message indicating that,
+    along with the value and event that triggered the snapshot:
+
+    # cat /sys/kernel/debug/tracing/events/tcp/tcp_probe/hist
+      { dport:       1521 } hitcount:          8
+	changed:         10  snd_wnd:      35456  srtt:     154262  rcv_wnd:      42112
+
+      { dport:         80 } hitcount:         23
+	changed:         10  snd_wnd:      28960  srtt:      19604  rcv_wnd:      29312
+
+      { dport:       9001 } hitcount:        172
+	changed:         10  snd_wnd:      48384  srtt:     260444  rcv_wnd:      55168
+
+      { dport:        443 } hitcount:        211
+	changed:         10  snd_wnd:      26960  srtt:      17379  rcv_wnd:      28800
+
+    Snapshot taken (see tracing/snapshot).  Details:
+        triggering value { onchange($cwnd) }:         10
+        triggered by event with key: { dport:         80 }
+
+    Totals:
+        Hits: 414
+        Entries: 4
+        Dropped: 0
+
+    In the above case, the event that triggered the snapshot has the
+    key with dport == 80.  If you look at the bucket that has 80 as
+    the key, you'll find the additional values save()'d along with the
+    changed value for that bucket, which should be the same as the
+    global changed value (since that was the same value that triggered
+    the global snapshot).
+
+    And finally, looking at the snapshot data should show at or near
+    the end the event that triggered the snapshot:
+
+    # cat /sys/kernel/debug/tracing/snapshot
+
+       gnome-shell-1261  [006] dN.3    49.823113: sched_stat_runtime: comm=gnome-shell pid=1261 runtime=49347 [ns] vruntime=1835730389 [ns]
+     kworker/u16:4-773   [003] d..3    49.823114: sched_switch: prev_comm=kworker/u16:4 prev_pid=773 prev_prio=120 prev_state=R+ ==> next_comm=kworker/3:2 next_pid=135 next_prio=120
+       gnome-shell-1261  [006] d..3    49.823114: sched_switch: prev_comm=gnome-shell prev_pid=1261 prev_prio=120 prev_state=R+ ==> next_comm=kworker/6:2 next_pid=387 next_prio=120
+       kworker/3:2-135   [003] d..3    49.823118: sched_stat_runtime: comm=kworker/3:2 pid=135 runtime=5339 [ns] vruntime=17815800388 [ns]
+       kworker/6:2-387   [006] d..3    49.823120: sched_stat_runtime: comm=kworker/6:2 pid=387 runtime=9594 [ns] vruntime=14589605367 [ns]
+       kworker/6:2-387   [006] d..3    49.823122: sched_switch: prev_comm=kworker/6:2 prev_pid=387 prev_prio=120 prev_state=R+ ==> next_comm=gnome-shell next_pid=1261 next_prio=120
+       kworker/3:2-135   [003] d..3    49.823123: sched_switch: prev_comm=kworker/3:2 prev_pid=135 prev_prio=120 prev_state=T ==> next_comm=swapper/3 next_pid=0 next_prio=120
+            <idle>-0     [004] ..s7    49.823798: tcp_probe: src=10.0.0.10:54326 dest=23.215.104.193:80 mark=0x0 length=32 snd_nxt=0xe3ae2ff5 snd_una=0xe3ae2ecd snd_cwnd=10 ssthresh=2147483647 snd_wnd=28960 srtt=19604 rcv_wnd=29312
+
 3. User space creating a trigger
 --------------------------------
 
diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst
index 4c3bfde2ba47..4346e23e3ae7 100644
--- a/Documentation/trace/uprobetracer.rst
+++ b/Documentation/trace/uprobetracer.rst
@@ -73,10 +73,9 @@ For $comm, the default type is "string"; any other type is invalid.
 
 Event Profiling
 ---------------
-You can check the total number of probe hits and probe miss-hits via
-/sys/kernel/debug/tracing/uprobe_profile.
-The first column is event name, the second is the number of probe hits,
-the third is the number of probe miss-hits.
+You can check the total number of probe hits per event via
+/sys/kernel/debug/tracing/uprobe_profile. The first column is the filename,
+the second is the event name, the third is the number of probe hits.
 
 Usage examples
 --------------
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 3e3789c8f8e1..ef49517f6bb2 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -49,7 +49,7 @@ int ftrace_arch_code_modify_post_process(void)
 union ftrace_code_union {
 	char code[MCOUNT_INSN_SIZE];
 	struct {
-		unsigned char e8;
+		unsigned char op;
 		int offset;
 	} __attribute__((packed));
 };
@@ -59,20 +59,23 @@ static int ftrace_calc_offset(long ip, long addr)
 	return (int)(addr - ip);
 }
 
-static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+static unsigned char *
+ftrace_text_replace(unsigned char op, unsigned long ip, unsigned long addr)
 {
 	static union ftrace_code_union calc;
 
-	calc.e8		= 0xe8;
+	calc.op		= op;
 	calc.offset	= ftrace_calc_offset(ip + MCOUNT_INSN_SIZE, addr);
 
-	/*
-	 * No locking needed, this must be called via kstop_machine
-	 * which in essence is like running on a uniprocessor machine.
-	 */
 	return calc.code;
 }
 
+static unsigned char *
+ftrace_call_replace(unsigned long ip, unsigned long addr)
+{
+	return ftrace_text_replace(0xe8, ip, addr);
+}
+
 static inline int
 within(unsigned long addr, unsigned long start, unsigned long end)
 {
@@ -665,22 +668,6 @@ int __init ftrace_dyn_arch_init(void)
 	return 0;
 }
 
-#if defined(CONFIG_X86_64) || defined(CONFIG_FUNCTION_GRAPH_TRACER)
-static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
-{
-	static union ftrace_code_union calc;
-
-	/* Jmp not a call (ignore the .e8) */
-	calc.e8		= 0xe9;
-	calc.offset	= ftrace_calc_offset(ip + MCOUNT_INSN_SIZE, addr);
-
-	/*
-	 * ftrace external locks synchronize the access to the static variable.
-	 */
-	return calc.code;
-}
-#endif
-
 /* Currently only x86_64 supports dynamic trampolines */
 #ifdef CONFIG_X86_64
 
@@ -892,8 +879,8 @@ static void *addr_from_call(void *ptr)
 		return NULL;
 
 	/* Make sure this is a call */
-	if (WARN_ON_ONCE(calc.e8 != 0xe8)) {
-		pr_warn("Expected e8, got %x\n", calc.e8);
+	if (WARN_ON_ONCE(calc.op != 0xe8)) {
+		pr_warn("Expected e8, got %x\n", calc.op);
 		return NULL;
 	}
 
@@ -964,6 +951,11 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
 #ifdef CONFIG_DYNAMIC_FTRACE
 extern void ftrace_graph_call(void);
 
+static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
+{
+	return ftrace_text_replace(0xe9, ip, addr);
+}
+
 static int ftrace_mod_jmp(unsigned long ip, void *func)
 {
 	unsigned char *new;
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 5b9ae62272bb..f1429675f252 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -187,8 +187,6 @@ void ring_buffer_set_clock(struct ring_buffer *buffer,
 void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs);
 bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer);
 
-size_t ring_buffer_page_len(void *page);
-
 size_t ring_buffer_nr_pages(struct ring_buffer *buffer, int cpu);
 size_t ring_buffer_nr_dirty_pages(struct ring_buffer *buffer, int cpu);
 
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index affa830a198c..c5cde87329c7 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -53,7 +53,7 @@ static struct percpu_rw_semaphore dup_mmap_sem;
 
 struct uprobe {
 	struct rb_node		rb_node;	/* node in the rb tree */
-	atomic_t		ref;
+	refcount_t		ref;
 	struct rw_semaphore	register_rwsem;
 	struct rw_semaphore	consumer_rwsem;
 	struct list_head	pending_list;
@@ -547,13 +547,13 @@ set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long v
 
 static struct uprobe *get_uprobe(struct uprobe *uprobe)
 {
-	atomic_inc(&uprobe->ref);
+	refcount_inc(&uprobe->ref);
 	return uprobe;
 }
 
 static void put_uprobe(struct uprobe *uprobe)
 {
-	if (atomic_dec_and_test(&uprobe->ref)) {
+	if (refcount_dec_and_test(&uprobe->ref)) {
 		/*
 		 * If application munmap(exec_vma) before uprobe_unregister()
 		 * gets called, we don't get a chance to remove uprobe from
@@ -644,7 +644,7 @@ static struct uprobe *__insert_uprobe(struct uprobe *uprobe)
 	rb_link_node(&uprobe->rb_node, parent, p);
 	rb_insert_color(&uprobe->rb_node, &uprobes_tree);
 	/* get access + creation ref */
-	atomic_set(&uprobe->ref, 2);
+	refcount_set(&uprobe->ref, 2);
 
 	return u;
 }
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index aac7847c0214..fa79323331b2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3702,6 +3702,31 @@ enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
 }
 
 static int
+add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
+		 int clear_filter)
+{
+	long index = simple_strtoul(func_g->search, NULL, 0);
+	struct ftrace_page *pg;
+	struct dyn_ftrace *rec;
+
+	/* The index starts at 1 */
+	if (--index < 0)
+		return 0;
+
+	do_for_each_ftrace_rec(pg, rec) {
+		if (pg->index <= index) {
+			index -= pg->index;
+			/* this is a double loop, break goes to the next page */
+			break;
+		}
+		rec = &pg->records[index];
+		enter_record(hash, rec, clear_filter);
+		return 1;
+	} while_for_each_ftrace_rec();
+	return 0;
+}
+
+static int
 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
 		struct ftrace_glob *mod_g, int exclude_mod)
 {
@@ -3769,6 +3794,11 @@ match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
 	if (unlikely(ftrace_disabled))
 		goto out_unlock;
 
+	if (func_g.type == MATCH_INDEX) {
+		found = add_rec_by_index(hash, &func_g, clear_filter);
+		goto out_unlock;
+	}
+
 	do_for_each_ftrace_rec(pg, rec) {
 
 		if (rec->flags & FTRACE_FL_DISABLED)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 06e864a334bb..9a91479bbbfe 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -353,20 +353,6 @@ static void rb_init_page(struct buffer_data_page *bpage)
 	local_set(&bpage->commit, 0);
 }
 
-/**
- * ring_buffer_page_len - the size of data on the page.
- * @page: The page to read
- *
- * Returns the amount of data on the page, including buffer page header.
- */
-size_t ring_buffer_page_len(void *page)
-{
-	struct buffer_data_page *bpage = page;
-
-	return (local_read(&bpage->commit) & ~RB_MISSED_FLAGS)
-		+ BUF_PAGE_HDR_SIZE;
-}
-
 /*
  * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
  * this issue out.
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c4238b441624..d7325eb1bc83 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -894,7 +894,7 @@ int __trace_bputs(unsigned long ip, const char *str)
 EXPORT_SYMBOL_GPL(__trace_bputs);
 
 #ifdef CONFIG_TRACER_SNAPSHOT
-void tracing_snapshot_instance(struct trace_array *tr)
+void tracing_snapshot_instance_cond(struct trace_array *tr, void *cond_data)
 {
 	struct tracer *tracer = tr->current_trace;
 	unsigned long flags;
@@ -920,10 +920,15 @@ void tracing_snapshot_instance(struct trace_array *tr)
 	}
 
 	local_irq_save(flags);
-	update_max_tr(tr, current, smp_processor_id());
+	update_max_tr(tr, current, smp_processor_id(), cond_data);
 	local_irq_restore(flags);
 }
 
+void tracing_snapshot_instance(struct trace_array *tr)
+{
+	tracing_snapshot_instance_cond(tr, NULL);
+}
+
 /**
  * tracing_snapshot - take a snapshot of the current buffer.
  *
@@ -946,6 +951,54 @@ void tracing_snapshot(void)
 }
 EXPORT_SYMBOL_GPL(tracing_snapshot);
 
+/**
+ * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
+ * @tr:		The tracing instance to snapshot
+ * @cond_data:	The data to be tested conditionally, and possibly saved
+ *
+ * This is the same as tracing_snapshot() except that the snapshot is
+ * conditional - the snapshot will only happen if the
+ * cond_snapshot.update() implementation receiving the cond_data
+ * returns true, which means that the trace array's cond_snapshot
+ * update() operation used the cond_data to determine whether the
+ * snapshot should be taken, and if it was, presumably saved it along
+ * with the snapshot.
+ */
+void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
+{
+	tracing_snapshot_instance_cond(tr, cond_data);
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
+
+/**
+ * tracing_snapshot_cond_data - get the user data associated with a snapshot
+ * @tr:		The tracing instance
+ *
+ * When the user enables a conditional snapshot using
+ * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
+ * with the snapshot.  This accessor is used to retrieve it.
+ *
+ * Should not be called from cond_snapshot.update(), since it takes
+ * the tr->max_lock lock, which the code calling
+ * cond_snapshot.update() has already done.
+ *
+ * Returns the cond_data associated with the trace array's snapshot.
+ */
+void *tracing_cond_snapshot_data(struct trace_array *tr)
+{
+	void *cond_data = NULL;
+
+	arch_spin_lock(&tr->max_lock);
+
+	if (tr->cond_snapshot)
+		cond_data = tr->cond_snapshot->cond_data;
+
+	arch_spin_unlock(&tr->max_lock);
+
+	return cond_data;
+}
+EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
+
 static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
 					struct trace_buffer *size_buf, int cpu_id);
 static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
@@ -1025,12 +1078,111 @@ void tracing_snapshot_alloc(void)
 	tracing_snapshot();
 }
 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
+
+/**
+ * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
+ * @tr:		The tracing instance
+ * @cond_data:	User data to associate with the snapshot
+ * @update:	Implementation of the cond_snapshot update function
+ *
+ * Check whether the conditional snapshot for the given instance has
+ * already been enabled, or if the current tracer is already using a
+ * snapshot; if so, return -EBUSY, else create a cond_snapshot and
+ * save the cond_data and update function inside.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
+				 cond_update_fn_t update)
+{
+	struct cond_snapshot *cond_snapshot;
+	int ret = 0;
+
+	cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
+	if (!cond_snapshot)
+		return -ENOMEM;
+
+	cond_snapshot->cond_data = cond_data;
+	cond_snapshot->update = update;
+
+	mutex_lock(&trace_types_lock);
+
+	ret = tracing_alloc_snapshot_instance(tr);
+	if (ret)
+		goto fail_unlock;
+
+	if (tr->current_trace->use_max_tr) {
+		ret = -EBUSY;
+		goto fail_unlock;
+	}
+
+	/*
+	 * The cond_snapshot can only change to NULL without the
+	 * trace_types_lock. We don't care if we race with it going
+	 * to NULL, but we want to make sure that it's not set to
+	 * something other than NULL when we get here, which we can
+	 * do safely with only holding the trace_types_lock and not
+	 * having to take the max_lock.
+	 */
+	if (tr->cond_snapshot) {
+		ret = -EBUSY;
+		goto fail_unlock;
+	}
+
+	arch_spin_lock(&tr->max_lock);
+	tr->cond_snapshot = cond_snapshot;
+	arch_spin_unlock(&tr->max_lock);
+
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+
+ fail_unlock:
+	mutex_unlock(&trace_types_lock);
+	kfree(cond_snapshot);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
+
+/**
+ * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
+ * @tr:		The tracing instance
+ *
+ * Check whether the conditional snapshot for the given instance is
+ * enabled; if so, free the cond_snapshot associated with it,
+ * otherwise return -EINVAL.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int tracing_snapshot_cond_disable(struct trace_array *tr)
+{
+	int ret = 0;
+
+	arch_spin_lock(&tr->max_lock);
+
+	if (!tr->cond_snapshot)
+		ret = -EINVAL;
+	else {
+		kfree(tr->cond_snapshot);
+		tr->cond_snapshot = NULL;
+	}
+
+	arch_spin_unlock(&tr->max_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
 #else
 void tracing_snapshot(void)
 {
 	WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
 }
 EXPORT_SYMBOL_GPL(tracing_snapshot);
+void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
+{
+	WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
 int tracing_alloc_snapshot(void)
 {
 	WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
@@ -1043,6 +1195,21 @@ void tracing_snapshot_alloc(void)
 	tracing_snapshot();
 }
 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
+void *tracing_cond_snapshot_data(struct trace_array *tr)
+{
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
+int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
+{
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
+int tracing_snapshot_cond_disable(struct trace_array *tr)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
 #endif /* CONFIG_TRACER_SNAPSHOT */
 
 void tracer_tracing_off(struct trace_array *tr)
@@ -1330,7 +1497,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 	max_data->critical_start = data->critical_start;
 	max_data->critical_end = data->critical_end;
 
-	memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
+	strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
 	max_data->pid = tsk->pid;
 	/*
 	 * If tsk == current, then use current_uid(), as that does not use
@@ -1354,12 +1521,14 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
  * @tr: tracer
  * @tsk: the task with the latency
  * @cpu: The cpu that initiated the trace.
+ * @cond_data: User data associated with a conditional snapshot
  *
  * Flip the buffers between the @tr and the max_tr and record information
  * about which task was the cause of this latency.
  */
 void
-update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
+update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
+	      void *cond_data)
 {
 	if (tr->stop_count)
 		return;
@@ -1380,9 +1549,15 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 	else
 		ring_buffer_record_off(tr->max_buffer.buffer);
 
+#ifdef CONFIG_TRACER_SNAPSHOT
+	if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data))
+		goto out_unlock;
+#endif
 	swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
 
 	__update_max_tr(tr, tsk, cpu);
+
+ out_unlock:
 	arch_spin_unlock(&tr->max_lock);
 }
 
@@ -1748,7 +1923,7 @@ static inline char *get_saved_cmdlines(int idx)
 
 static inline void set_cmdline(int idx, const char *cmdline)
 {
-	memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
+	strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
 }
 
 static int allocate_cmdlines_buffer(unsigned int val,
@@ -4702,6 +4877,7 @@ static const char readme_msg[] =
 	"\t            [:size=#entries]\n"
 	"\t            [:pause][:continue][:clear]\n"
 	"\t            [:name=histname1]\n"
+	"\t            [:<handler>.<action>]\n"
 	"\t            [if <filter>]\n\n"
 	"\t    When a matching event is hit, an entry is added to a hash\n"
 	"\t    table using the key(s) and value(s) named, and the value of a\n"
@@ -4742,8 +4918,21 @@ static const char readme_msg[] =
 	"\t    unchanged.\n\n"
 	"\t    The enable_hist and disable_hist triggers can be used to\n"
 	"\t    have one event conditionally start and stop another event's\n"
-	"\t    already-attached hist trigger.  The syntax is analagous to\n"
-	"\t    the enable_event and disable_event triggers.\n"
+	"\t    already-attached hist trigger.  The syntax is analogous to\n"
+	"\t    the enable_event and disable_event triggers.\n\n"
+	"\t    Hist trigger handlers and actions are executed whenever a\n"
+	"\t    a histogram entry is added or updated.  They take the form:\n\n"
+	"\t        <handler>.<action>\n\n"
+	"\t    The available handlers are:\n\n"
+	"\t        onmatch(matching.event)  - invoke on addition or update\n"
+	"\t        onmax(var)               - invoke if var exceeds current max\n"
+	"\t        onchange(var)            - invoke action if var changes\n\n"
+	"\t    The available actions are:\n\n"
+	"\t        trace(<synthetic_event>,param list)  - generate synthetic event\n"
+	"\t        save(field,...)                      - save current event fields\n"
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\t        snapshot()                           - snapshot the trace buffer\n"
+#endif
 #endif
 ;
 
@@ -5388,6 +5577,16 @@ static int tracing_set_tracer(struct trace_array *tr, const char *buf)
 	if (t == tr->current_trace)
 		goto out;
 
+#ifdef CONFIG_TRACER_SNAPSHOT
+	if (t->use_max_tr) {
+		arch_spin_lock(&tr->max_lock);
+		if (tr->cond_snapshot)
+			ret = -EBUSY;
+		arch_spin_unlock(&tr->max_lock);
+		if (ret)
+			goto out;
+	}
+#endif
 	/* Some tracers won't work on kernel command line */
 	if (system_state < SYSTEM_RUNNING && t->noboot) {
 		pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
@@ -5626,7 +5825,6 @@ out:
 	return ret;
 
 fail:
-	kfree(iter->trace);
 	kfree(iter);
 	__trace_array_put(tr);
 	mutex_unlock(&trace_types_lock);
@@ -6470,6 +6668,13 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		goto out;
 	}
 
+	arch_spin_lock(&tr->max_lock);
+	if (tr->cond_snapshot)
+		ret = -EBUSY;
+	arch_spin_unlock(&tr->max_lock);
+	if (ret)
+		goto out;
+
 	switch (val) {
 	case 0:
 		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
@@ -6495,7 +6700,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		local_irq_disable();
 		/* Now, we're going to swap */
 		if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
-			update_max_tr(tr, current, smp_processor_id());
+			update_max_tr(tr, current, smp_processor_id(), NULL);
 		else
 			update_max_tr_single(tr, current, iter->cpu_file);
 		local_irq_enable();
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 08900828d282..d80cee49e0eb 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -194,6 +194,51 @@ struct trace_pid_list {
 	unsigned long			*pids;
 };
 
+typedef bool (*cond_update_fn_t)(struct trace_array *tr, void *cond_data);
+
+/**
+ * struct cond_snapshot - conditional snapshot data and callback
+ *
+ * The cond_snapshot structure encapsulates a callback function and
+ * data associated with the snapshot for a given tracing instance.
+ *
+ * When a snapshot is taken conditionally, by invoking
+ * tracing_snapshot_cond(tr, cond_data), the cond_data passed in is
+ * passed in turn to the cond_snapshot.update() function.  That data
+ * can be compared by the update() implementation with the cond_data
+ * contained wihin the struct cond_snapshot instance associated with
+ * the trace_array.  Because the tr->max_lock is held throughout the
+ * update() call, the update() function can directly retrieve the
+ * cond_snapshot and cond_data associated with the per-instance
+ * snapshot associated with the trace_array.
+ *
+ * The cond_snapshot.update() implementation can save data to be
+ * associated with the snapshot if it decides to, and returns 'true'
+ * in that case, or it returns 'false' if the conditional snapshot
+ * shouldn't be taken.
+ *
+ * The cond_snapshot instance is created and associated with the
+ * user-defined cond_data by tracing_cond_snapshot_enable().
+ * Likewise, the cond_snapshot instance is destroyed and is no longer
+ * associated with the trace instance by
+ * tracing_cond_snapshot_disable().
+ *
+ * The method below is required.
+ *
+ * @update: When a conditional snapshot is invoked, the update()
+ *	callback function is invoked with the tr->max_lock held.  The
+ *	update() implementation signals whether or not to actually
+ *	take the snapshot, by returning 'true' if so, 'false' if no
+ *	snapshot should be taken.  Because the max_lock is held for
+ *	the duration of update(), the implementation is safe to
+ *	directly retrieven and save any implementation data it needs
+ *	to in association with the snapshot.
+ */
+struct cond_snapshot {
+	void				*cond_data;
+	cond_update_fn_t		update;
+};
+
 /*
  * The trace array - an array of per-CPU trace arrays. This is the
  * highest level data structure that individual tracers deal with.
@@ -277,6 +322,9 @@ struct trace_array {
 #endif
 	int			time_stamp_abs_ref;
 	struct list_head	hist_vars;
+#ifdef CONFIG_TRACER_SNAPSHOT
+	struct cond_snapshot	*cond_snapshot;
+#endif
 };
 
 enum {
@@ -727,7 +775,8 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
 		    const char __user *ubuf, size_t cnt);
 
 #ifdef CONFIG_TRACER_MAX_TRACE
-void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
+void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
+		   void *cond_data);
 void update_max_tr_single(struct trace_array *tr,
 			  struct task_struct *tsk, int cpu);
 #endif /* CONFIG_TRACER_MAX_TRACE */
@@ -855,10 +904,11 @@ static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
 #define TRACE_GRAPH_PRINT_PROC          0x8
 #define TRACE_GRAPH_PRINT_DURATION      0x10
 #define TRACE_GRAPH_PRINT_ABS_TIME      0x20
-#define TRACE_GRAPH_PRINT_IRQS          0x40
-#define TRACE_GRAPH_PRINT_TAIL          0x80
-#define TRACE_GRAPH_SLEEP_TIME		0x100
-#define TRACE_GRAPH_GRAPH_TIME		0x200
+#define TRACE_GRAPH_PRINT_REL_TIME      0x40
+#define TRACE_GRAPH_PRINT_IRQS          0x80
+#define TRACE_GRAPH_PRINT_TAIL          0x100
+#define TRACE_GRAPH_SLEEP_TIME          0x200
+#define TRACE_GRAPH_GRAPH_TIME          0x400
 #define TRACE_GRAPH_PRINT_FILL_SHIFT	28
 #define TRACE_GRAPH_PRINT_FILL_MASK	(0x3 << TRACE_GRAPH_PRINT_FILL_SHIFT)
 
@@ -1458,6 +1508,7 @@ enum regex_type {
 	MATCH_MIDDLE_ONLY,
 	MATCH_END_ONLY,
 	MATCH_GLOB,
+	MATCH_INDEX,
 };
 
 struct regex {
@@ -1808,6 +1859,11 @@ static inline bool event_command_needs_rec(struct event_command *cmd_ops)
 extern int trace_event_enable_disable(struct trace_event_file *file,
 				      int enable, int soft_disable);
 extern int tracing_alloc_snapshot(void);
+extern void tracing_snapshot_cond(struct trace_array *tr, void *cond_data);
+extern int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update);
+
+extern int tracing_snapshot_cond_disable(struct trace_array *tr);
+extern void *tracing_cond_snapshot_data(struct trace_array *tr);
 
 extern const char *__start___trace_bprintk_fmt[];
 extern const char *__stop___trace_bprintk_fmt[];
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index 06bb2fd9a56c..fc8e97328e54 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -65,7 +65,8 @@ FTRACE_ENTRY_REG(function, ftrace_entry,
 		__field(	unsigned long,	parent_ip	)
 	),
 
-	F_printk(" %lx <-- %lx", __entry->ip, __entry->parent_ip),
+	F_printk(" %ps <-- %ps",
+		 (void *)__entry->ip, (void *)__entry->parent_ip),
 
 	FILTER_TRACE_FN,
 
@@ -83,7 +84,7 @@ FTRACE_ENTRY_PACKED(funcgraph_entry, ftrace_graph_ent_entry,
 		__field_desc(	int,		graph_ent,	depth		)
 	),
 
-	F_printk("--> %lx (%d)", __entry->func, __entry->depth),
+	F_printk("--> %ps (%d)", (void *)__entry->func, __entry->depth),
 
 	FILTER_OTHER
 );
@@ -102,8 +103,8 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry,
 		__field_desc(	int,		ret,		depth	)
 	),
 
-	F_printk("<-- %lx (%d) (start: %llx  end: %llx) over: %d",
-		 __entry->func, __entry->depth,
+	F_printk("<-- %ps (%d) (start: %llx  end: %llx) over: %d",
+		 (void *)__entry->func, __entry->depth,
 		 __entry->calltime, __entry->rettime,
 		 __entry->depth),
 
@@ -167,12 +168,6 @@ FTRACE_ENTRY_DUP(wakeup, ctx_switch_entry,
 
 #define FTRACE_STACK_ENTRIES	8
 
-#ifndef CONFIG_64BIT
-# define IP_FMT "%08lx"
-#else
-# define IP_FMT "%016lx"
-#endif
-
 FTRACE_ENTRY(kernel_stack, stack_entry,
 
 	TRACE_STACK,
@@ -182,12 +177,13 @@ FTRACE_ENTRY(kernel_stack, stack_entry,
 		__dynamic_array(unsigned long,	caller	)
 	),
 
-	F_printk("\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n"
-		 "\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n"
-		 "\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n",
-		 __entry->caller[0], __entry->caller[1], __entry->caller[2],
-		 __entry->caller[3], __entry->caller[4], __entry->caller[5],
-		 __entry->caller[6], __entry->caller[7]),
+	F_printk("\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n",
+		 (void *)__entry->caller[0], (void *)__entry->caller[1],
+		 (void *)__entry->caller[2], (void *)__entry->caller[3],
+		 (void *)__entry->caller[4], (void *)__entry->caller[5],
+		 (void *)__entry->caller[6], (void *)__entry->caller[7]),
 
 	FILTER_OTHER
 );
@@ -201,12 +197,13 @@ FTRACE_ENTRY(user_stack, userstack_entry,
 		__array(	unsigned long,	caller, FTRACE_STACK_ENTRIES	)
 	),
 
-	F_printk("\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n"
-		 "\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n"
-		 "\t=> (" IP_FMT ")\n\t=> (" IP_FMT ")\n",
-		 __entry->caller[0], __entry->caller[1], __entry->caller[2],
-		 __entry->caller[3], __entry->caller[4], __entry->caller[5],
-		 __entry->caller[6], __entry->caller[7]),
+	F_printk("\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n\t=> %ps\n"
+		 "\t=> %ps\n\t=> %ps\n",
+		 (void *)__entry->caller[0], (void *)__entry->caller[1],
+		 (void *)__entry->caller[2], (void *)__entry->caller[3],
+		 (void *)__entry->caller[4], (void *)__entry->caller[5],
+		 (void *)__entry->caller[6], (void *)__entry->caller[7]),
 
 	FILTER_OTHER
 );
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 76217bbef815..4629a6104474 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -299,15 +299,13 @@ int perf_uprobe_init(struct perf_event *p_event,
 
 	if (!p_event->attr.uprobe_path)
 		return -EINVAL;
-	path = kzalloc(PATH_MAX, GFP_KERNEL);
-	if (!path)
-		return -ENOMEM;
-	ret = strncpy_from_user(
-		path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);
-	if (ret == PATH_MAX)
-		return -E2BIG;
-	if (ret < 0)
-		goto out;
+
+	path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path),
+			    PATH_MAX);
+	if (IS_ERR(path)) {
+		ret = PTR_ERR(path);
+		return (ret == -EINVAL) ? -E2BIG : ret;
+	}
 	if (path[0] == '\0') {
 		ret = -EINVAL;
 		goto out;
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 217ef481fbbb..05a66493a164 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -491,10 +491,12 @@ predicate_parse(const char *str, int nr_parens, int nr_preds,
 				break;
 			case '&':
 			case '|':
+				/* accepting only "&&" or "||" */
 				if (next[1] == next[0]) {
 					ptr++;
 					break;
 				}
+				/* fall through */
 			default:
 				parse_error(pe, FILT_ERR_TOO_MANY_PREDS,
 					    next - str);
@@ -823,6 +825,9 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
 
 	*search = buff;
 
+	if (isdigit(buff[0]))
+		return MATCH_INDEX;
+
 	for (i = 0; i < len; i++) {
 		if (buff[i] == '*') {
 			if (!i) {
@@ -860,6 +865,8 @@ static void filter_build_regex(struct filter_pred *pred)
 	}
 
 	switch (type) {
+	/* MATCH_INDEX should not happen, but if it does, match full */
+	case MATCH_INDEX:
 	case MATCH_FULL:
 		r->match = regex_match_full;
 		break;
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 449d90cfa151..ca46339f3009 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -313,9 +313,9 @@ struct hist_trigger_data {
 	struct field_var_hist		*field_var_hists[SYNTH_FIELDS_MAX];
 	unsigned int			n_field_var_hists;
 
-	struct field_var		*max_vars[SYNTH_FIELDS_MAX];
-	unsigned int			n_max_vars;
-	unsigned int			n_max_var_str;
+	struct field_var		*save_vars[SYNTH_FIELDS_MAX];
+	unsigned int			n_save_vars;
+	unsigned int			n_save_var_str;
 };
 
 static int synth_event_create(int argc, const char **argv);
@@ -383,41 +383,157 @@ struct action_data;
 
 typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
 			     struct tracing_map_elt *elt, void *rec,
-			     struct ring_buffer_event *rbe,
+			     struct ring_buffer_event *rbe, void *key,
 			     struct action_data *data, u64 *var_ref_vals);
 
+typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);
+
+enum handler_id {
+	HANDLER_ONMATCH = 1,
+	HANDLER_ONMAX,
+	HANDLER_ONCHANGE,
+};
+
+enum action_id {
+	ACTION_SAVE = 1,
+	ACTION_TRACE,
+	ACTION_SNAPSHOT,
+};
+
 struct action_data {
+	enum handler_id		handler;
+	enum action_id		action;
+	char			*action_name;
 	action_fn_t		fn;
+
 	unsigned int		n_params;
 	char			*params[SYNTH_FIELDS_MAX];
 
+	/*
+	 * When a histogram trigger is hit, the values of any
+	 * references to variables, including variables being passed
+	 * as parameters to synthetic events, are collected into a
+	 * var_ref_vals array.  This var_ref_idx is the index of the
+	 * first param in the array to be passed to the synthetic
+	 * event invocation.
+	 */
+	unsigned int		var_ref_idx;
+	struct synth_event	*synth_event;
+	bool			use_trace_keyword;
+	char			*synth_event_name;
+
 	union {
 		struct {
-			/*
-			 * When a histogram trigger is hit, the values of any
-			 * references to variables, including variables being passed
-			 * as parameters to synthetic events, are collected into a
-			 * var_ref_vals array.  This var_ref_idx is the index of the
-			 * first param in the array to be passed to the synthetic
-			 * event invocation.
-			 */
-			unsigned int		var_ref_idx;
-			char			*match_event;
-			char			*match_event_system;
-			char			*synth_event_name;
-			struct synth_event	*synth_event;
-		} onmatch;
+			char			*event;
+			char			*event_system;
+		} match_data;
 
 		struct {
+			/*
+			 * var_str contains the $-unstripped variable
+			 * name referenced by var_ref, and used when
+			 * printing the action.  Because var_ref
+			 * creation is deferred to create_actions(),
+			 * we need a per-action way to save it until
+			 * then, thus var_str.
+			 */
 			char			*var_str;
-			char			*fn_name;
-			unsigned int		max_var_ref_idx;
-			struct hist_field	*max_var;
-			struct hist_field	*var;
-		} onmax;
+
+			/*
+			 * var_ref refers to the variable being
+			 * tracked e.g onmax($var).
+			 */
+			struct hist_field	*var_ref;
+
+			/*
+			 * track_var contains the 'invisible' tracking
+			 * variable created to keep the current
+			 * e.g. max value.
+			 */
+			struct hist_field	*track_var;
+
+			check_track_val_fn_t	check_val;
+			action_fn_t		save_data;
+		} track_data;
 	};
 };
 
+struct track_data {
+	u64				track_val;
+	bool				updated;
+
+	unsigned int			key_len;
+	void				*key;
+	struct tracing_map_elt		elt;
+
+	struct action_data		*action_data;
+	struct hist_trigger_data	*hist_data;
+};
+
+struct hist_elt_data {
+	char *comm;
+	u64 *var_ref_vals;
+	char *field_var_str[SYNTH_FIELDS_MAX];
+};
+
+struct snapshot_context {
+	struct tracing_map_elt	*elt;
+	void			*key;
+};
+
+static void track_data_free(struct track_data *track_data)
+{
+	struct hist_elt_data *elt_data;
+
+	if (!track_data)
+		return;
+
+	kfree(track_data->key);
+
+	elt_data = track_data->elt.private_data;
+	if (elt_data) {
+		kfree(elt_data->comm);
+		kfree(elt_data);
+	}
+
+	kfree(track_data);
+}
+
+static struct track_data *track_data_alloc(unsigned int key_len,
+					   struct action_data *action_data,
+					   struct hist_trigger_data *hist_data)
+{
+	struct track_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
+	struct hist_elt_data *elt_data;
+
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	data->key = kzalloc(key_len, GFP_KERNEL);
+	if (!data->key) {
+		track_data_free(data);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	data->key_len = key_len;
+	data->action_data = action_data;
+	data->hist_data = hist_data;
+
+	elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
+	if (!elt_data) {
+		track_data_free(data);
+		return ERR_PTR(-ENOMEM);
+	}
+	data->elt.private_data = elt_data;
+
+	elt_data->comm = kzalloc(TASK_COMM_LEN, GFP_KERNEL);
+	if (!elt_data->comm) {
+		track_data_free(data);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return data;
+}
 
 static char last_hist_cmd[MAX_FILTER_STR_VAL];
 static char hist_err_str[MAX_FILTER_STR_VAL];
@@ -1078,12 +1194,12 @@ static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 
 static void action_trace(struct hist_trigger_data *hist_data,
 			 struct tracing_map_elt *elt, void *rec,
-			 struct ring_buffer_event *rbe,
+			 struct ring_buffer_event *rbe, void *key,
 			 struct action_data *data, u64 *var_ref_vals)
 {
-	struct synth_event *event = data->onmatch.synth_event;
+	struct synth_event *event = data->synth_event;
 
-	trace_synth(event, var_ref_vals, data->onmatch.var_ref_idx);
+	trace_synth(event, var_ref_vals, data->var_ref_idx);
 }
 
 struct hist_var_data {
@@ -1200,8 +1316,8 @@ static int synth_event_create(int argc, const char **argv)
 
 	/* This interface accepts group name prefix */
 	if (strchr(name, '/')) {
-		len = sizeof(SYNTH_SYSTEM "/") - 1;
-		if (strncmp(name, SYNTH_SYSTEM "/", len))
+		len = str_has_prefix(name, SYNTH_SYSTEM "/");
+		if (len == 0)
 			return -EINVAL;
 		name += len;
 	}
@@ -1644,9 +1760,9 @@ find_match_var(struct hist_trigger_data *hist_data, char *var_name)
 	for (i = 0; i < hist_data->n_actions; i++) {
 		struct action_data *data = hist_data->actions[i];
 
-		if (data->fn == action_trace) {
-			char *system = data->onmatch.match_event_system;
-			char *event_name = data->onmatch.match_event;
+		if (data->handler == HANDLER_ONMATCH) {
+			char *system = data->match_data.event_system;
+			char *event_name = data->match_data.event;
 
 			file = find_var_file(tr, system, event_name, var_name);
 			if (!file)
@@ -1691,12 +1807,6 @@ static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
 	return hist_field;
 }
 
-struct hist_elt_data {
-	char *comm;
-	u64 *var_ref_vals;
-	char *field_var_str[SYNTH_FIELDS_MAX];
-};
-
 static u64 hist_field_var_ref(struct hist_field *hist_field,
 			      struct tracing_map_elt *elt,
 			      struct ring_buffer_event *rbe,
@@ -1882,7 +1992,8 @@ static int parse_action(char *str, struct hist_trigger_attrs *attrs)
 		return ret;
 
 	if ((str_has_prefix(str, "onmatch(")) ||
-	    (str_has_prefix(str, "onmax("))) {
+	    (str_has_prefix(str, "onmax(")) ||
+	    (str_has_prefix(str, "onchange("))) {
 		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
 		if (!attrs->action_str[attrs->n_actions]) {
 			ret = -ENOMEM;
@@ -2030,7 +2141,7 @@ static inline void save_comm(char *comm, struct task_struct *task)
 		return;
 	}
 
-	memcpy(comm, task->comm, TASK_COMM_LEN);
+	strncpy(comm, task->comm, TASK_COMM_LEN);
 }
 
 static void hist_elt_data_free(struct hist_elt_data *elt_data)
@@ -2076,7 +2187,7 @@ static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
 		}
 	}
 
-	n_str = hist_data->n_field_var_str + hist_data->n_max_var_str;
+	n_str = hist_data->n_field_var_str + hist_data->n_save_var_str;
 
 	size = STR_VAR_LEN_MAX;
 
@@ -3050,7 +3161,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data,
 	int ret;
 
 	if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
-		hist_err_event("onmatch: Too many field variables defined: ",
+		hist_err_event("trace action: Too many field variables defined: ",
 			       subsys_name, event_name, field_name);
 		return ERR_PTR(-EINVAL);
 	}
@@ -3058,7 +3169,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data,
 	file = event_file(tr, subsys_name, event_name);
 
 	if (IS_ERR(file)) {
-		hist_err_event("onmatch: Event file not found: ",
+		hist_err_event("trace action: Event file not found: ",
 			       subsys_name, event_name, field_name);
 		ret = PTR_ERR(file);
 		return ERR_PTR(ret);
@@ -3072,7 +3183,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data,
 	 */
 	hist_data = find_compatible_hist(target_hist_data, file);
 	if (!hist_data) {
-		hist_err_event("onmatch: Matching event histogram not found: ",
+		hist_err_event("trace action: Matching event histogram not found: ",
 			       subsys_name, event_name, field_name);
 		return ERR_PTR(-EINVAL);
 	}
@@ -3134,7 +3245,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data,
 		kfree(cmd);
 		kfree(var_hist->cmd);
 		kfree(var_hist);
-		hist_err_event("onmatch: Couldn't create histogram for field: ",
+		hist_err_event("trace action: Couldn't create histogram for field: ",
 			       subsys_name, event_name, field_name);
 		return ERR_PTR(ret);
 	}
@@ -3147,7 +3258,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data,
 	if (IS_ERR_OR_NULL(event_var)) {
 		kfree(var_hist->cmd);
 		kfree(var_hist);
-		hist_err_event("onmatch: Couldn't find synthetic variable: ",
+		hist_err_event("trace action: Couldn't find synthetic variable: ",
 			       subsys_name, event_name, field_name);
 		return ERR_PTR(-EINVAL);
 	}
@@ -3225,13 +3336,13 @@ static void update_field_vars(struct hist_trigger_data *hist_data,
 			    hist_data->n_field_vars, 0);
 }
 
-static void update_max_vars(struct hist_trigger_data *hist_data,
-			    struct tracing_map_elt *elt,
-			    struct ring_buffer_event *rbe,
-			    void *rec)
+static void save_track_data_vars(struct hist_trigger_data *hist_data,
+				 struct tracing_map_elt *elt, void *rec,
+				 struct ring_buffer_event *rbe, void *key,
+				 struct action_data *data, u64 *var_ref_vals)
 {
-	__update_field_vars(elt, rbe, rec, hist_data->max_vars,
-			    hist_data->n_max_vars, hist_data->n_field_var_str);
+	__update_field_vars(elt, rbe, rec, hist_data->save_vars,
+			    hist_data->n_save_vars, hist_data->n_field_var_str);
 }
 
 static struct hist_field *create_var(struct hist_trigger_data *hist_data,
@@ -3366,18 +3477,190 @@ create_target_field_var(struct hist_trigger_data *target_hist_data,
 	return create_field_var(target_hist_data, file, var_name);
 }
 
-static void onmax_print(struct seq_file *m,
-			struct hist_trigger_data *hist_data,
-			struct tracing_map_elt *elt,
-			struct action_data *data)
+static bool check_track_val_max(u64 track_val, u64 var_val)
 {
-	unsigned int i, save_var_idx, max_idx = data->onmax.max_var->var.idx;
+	if (var_val <= track_val)
+		return false;
+
+	return true;
+}
 
-	seq_printf(m, "\n\tmax: %10llu", tracing_map_read_var(elt, max_idx));
+static bool check_track_val_changed(u64 track_val, u64 var_val)
+{
+	if (var_val == track_val)
+		return false;
+
+	return true;
+}
+
+static u64 get_track_val(struct hist_trigger_data *hist_data,
+			 struct tracing_map_elt *elt,
+			 struct action_data *data)
+{
+	unsigned int track_var_idx = data->track_data.track_var->var.idx;
+	u64 track_val;
+
+	track_val = tracing_map_read_var(elt, track_var_idx);
+
+	return track_val;
+}
+
+static void save_track_val(struct hist_trigger_data *hist_data,
+			   struct tracing_map_elt *elt,
+			   struct action_data *data, u64 var_val)
+{
+	unsigned int track_var_idx = data->track_data.track_var->var.idx;
+
+	tracing_map_set_var(elt, track_var_idx, var_val);
+}
+
+static void save_track_data(struct hist_trigger_data *hist_data,
+			    struct tracing_map_elt *elt, void *rec,
+			    struct ring_buffer_event *rbe, void *key,
+			    struct action_data *data, u64 *var_ref_vals)
+{
+	if (data->track_data.save_data)
+		data->track_data.save_data(hist_data, elt, rec, rbe, key, data, var_ref_vals);
+}
+
+static bool check_track_val(struct tracing_map_elt *elt,
+			    struct action_data *data,
+			    u64 var_val)
+{
+	struct hist_trigger_data *hist_data;
+	u64 track_val;
+
+	hist_data = data->track_data.track_var->hist_data;
+	track_val = get_track_val(hist_data, elt, data);
+
+	return data->track_data.check_val(track_val, var_val);
+}
 
-	for (i = 0; i < hist_data->n_max_vars; i++) {
-		struct hist_field *save_val = hist_data->max_vars[i]->val;
-		struct hist_field *save_var = hist_data->max_vars[i]->var;
+#ifdef CONFIG_TRACER_SNAPSHOT
+static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
+{
+	/* called with tr->max_lock held */
+	struct track_data *track_data = tr->cond_snapshot->cond_data;
+	struct hist_elt_data *elt_data, *track_elt_data;
+	struct snapshot_context *context = cond_data;
+	u64 track_val;
+
+	if (!track_data)
+		return false;
+
+	track_val = get_track_val(track_data->hist_data, context->elt,
+				  track_data->action_data);
+
+	track_data->track_val = track_val;
+	memcpy(track_data->key, context->key, track_data->key_len);
+
+	elt_data = context->elt->private_data;
+	track_elt_data = track_data->elt.private_data;
+	if (elt_data->comm)
+		strncpy(track_elt_data->comm, elt_data->comm, TASK_COMM_LEN);
+
+	track_data->updated = true;
+
+	return true;
+}
+
+static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
+				     struct tracing_map_elt *elt, void *rec,
+				     struct ring_buffer_event *rbe, void *key,
+				     struct action_data *data,
+				     u64 *var_ref_vals)
+{
+	struct trace_event_file *file = hist_data->event_file;
+	struct snapshot_context context;
+
+	context.elt = elt;
+	context.key = key;
+
+	tracing_snapshot_cond(file->tr, &context);
+}
+
+static void hist_trigger_print_key(struct seq_file *m,
+				   struct hist_trigger_data *hist_data,
+				   void *key,
+				   struct tracing_map_elt *elt);
+
+static struct action_data *snapshot_action(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	if (!hist_data->n_actions)
+		return NULL;
+
+	for (i = 0; i < hist_data->n_actions; i++) {
+		struct action_data *data = hist_data->actions[i];
+
+		if (data->action == ACTION_SNAPSHOT)
+			return data;
+	}
+
+	return NULL;
+}
+
+static void track_data_snapshot_print(struct seq_file *m,
+				      struct hist_trigger_data *hist_data)
+{
+	struct trace_event_file *file = hist_data->event_file;
+	struct track_data *track_data;
+	struct action_data *action;
+
+	track_data = tracing_cond_snapshot_data(file->tr);
+	if (!track_data)
+		return;
+
+	if (!track_data->updated)
+		return;
+
+	action = snapshot_action(hist_data);
+	if (!action)
+		return;
+
+	seq_puts(m, "\nSnapshot taken (see tracing/snapshot).  Details:\n");
+	seq_printf(m, "\ttriggering value { %s(%s) }: %10llu",
+		   action->handler == HANDLER_ONMAX ? "onmax" : "onchange",
+		   action->track_data.var_str, track_data->track_val);
+
+	seq_puts(m, "\ttriggered by event with key: ");
+	hist_trigger_print_key(m, hist_data, track_data->key, &track_data->elt);
+	seq_putc(m, '\n');
+}
+#else
+static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
+{
+	return false;
+}
+static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
+				     struct tracing_map_elt *elt, void *rec,
+				     struct ring_buffer_event *rbe, void *key,
+				     struct action_data *data,
+				     u64 *var_ref_vals) {}
+static void track_data_snapshot_print(struct seq_file *m,
+				      struct hist_trigger_data *hist_data) {}
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+static void track_data_print(struct seq_file *m,
+			     struct hist_trigger_data *hist_data,
+			     struct tracing_map_elt *elt,
+			     struct action_data *data)
+{
+	u64 track_val = get_track_val(hist_data, elt, data);
+	unsigned int i, save_var_idx;
+
+	if (data->handler == HANDLER_ONMAX)
+		seq_printf(m, "\n\tmax: %10llu", track_val);
+	else if (data->handler == HANDLER_ONCHANGE)
+		seq_printf(m, "\n\tchanged: %10llu", track_val);
+
+	if (data->action == ACTION_SNAPSHOT)
+		return;
+
+	for (i = 0; i < hist_data->n_save_vars; i++) {
+		struct hist_field *save_val = hist_data->save_vars[i]->val;
+		struct hist_field *save_var = hist_data->save_vars[i]->var;
 		u64 val;
 
 		save_var_idx = save_var->var.idx;
@@ -3392,64 +3675,82 @@ static void onmax_print(struct seq_file *m,
 	}
 }
 
-static void onmax_save(struct hist_trigger_data *hist_data,
-		       struct tracing_map_elt *elt, void *rec,
-		       struct ring_buffer_event *rbe,
-		       struct action_data *data, u64 *var_ref_vals)
+static void ontrack_action(struct hist_trigger_data *hist_data,
+			   struct tracing_map_elt *elt, void *rec,
+			   struct ring_buffer_event *rbe, void *key,
+			   struct action_data *data, u64 *var_ref_vals)
 {
-	unsigned int max_idx = data->onmax.max_var->var.idx;
-	unsigned int max_var_ref_idx = data->onmax.max_var_ref_idx;
+	u64 var_val = var_ref_vals[data->track_data.var_ref->var_ref_idx];
 
-	u64 var_val, max_val;
-
-	var_val = var_ref_vals[max_var_ref_idx];
-	max_val = tracing_map_read_var(elt, max_idx);
-
-	if (var_val <= max_val)
-		return;
-
-	tracing_map_set_var(elt, max_idx, var_val);
-
-	update_max_vars(hist_data, elt, rbe, rec);
+	if (check_track_val(elt, data, var_val)) {
+		save_track_val(hist_data, elt, data, var_val);
+		save_track_data(hist_data, elt, rec, rbe, key, data, var_ref_vals);
+	}
 }
 
-static void onmax_destroy(struct action_data *data)
+static void action_data_destroy(struct action_data *data)
 {
 	unsigned int i;
 
-	destroy_hist_field(data->onmax.max_var, 0);
-	destroy_hist_field(data->onmax.var, 0);
+	lockdep_assert_held(&event_mutex);
 
-	kfree(data->onmax.var_str);
-	kfree(data->onmax.fn_name);
+	kfree(data->action_name);
 
 	for (i = 0; i < data->n_params; i++)
 		kfree(data->params[i]);
 
+	if (data->synth_event)
+		data->synth_event->ref--;
+
+	kfree(data->synth_event_name);
+
 	kfree(data);
 }
 
-static int onmax_create(struct hist_trigger_data *hist_data,
-			struct action_data *data)
+static void track_data_destroy(struct hist_trigger_data *hist_data,
+			       struct action_data *data)
 {
 	struct trace_event_file *file = hist_data->event_file;
-	struct hist_field *var_field, *ref_field, *max_var;
-	unsigned int var_ref_idx = hist_data->n_var_refs;
-	struct field_var *field_var;
-	char *onmax_var_str, *param;
-	unsigned int i;
+
+	destroy_hist_field(data->track_data.track_var, 0);
+	destroy_hist_field(data->track_data.var_ref, 0);
+
+	if (data->action == ACTION_SNAPSHOT) {
+		struct track_data *track_data;
+
+		track_data = tracing_cond_snapshot_data(file->tr);
+		if (track_data && track_data->hist_data == hist_data) {
+			tracing_snapshot_cond_disable(file->tr);
+			track_data_free(track_data);
+		}
+	}
+
+	kfree(data->track_data.var_str);
+
+	action_data_destroy(data);
+}
+
+static int action_create(struct hist_trigger_data *hist_data,
+			 struct action_data *data);
+
+static int track_data_create(struct hist_trigger_data *hist_data,
+			     struct action_data *data)
+{
+	struct hist_field *var_field, *ref_field, *track_var = NULL;
+	struct trace_event_file *file = hist_data->event_file;
+	char *track_data_var_str;
 	int ret = 0;
 
-	onmax_var_str = data->onmax.var_str;
-	if (onmax_var_str[0] != '$') {
-		hist_err("onmax: For onmax(x), x must be a variable: ", onmax_var_str);
+	track_data_var_str = data->track_data.var_str;
+	if (track_data_var_str[0] != '$') {
+		hist_err("For onmax(x) or onchange(x), x must be a variable: ", track_data_var_str);
 		return -EINVAL;
 	}
-	onmax_var_str++;
+	track_data_var_str++;
 
-	var_field = find_target_event_var(hist_data, NULL, NULL, onmax_var_str);
+	var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
 	if (!var_field) {
-		hist_err("onmax: Couldn't find onmax variable: ", onmax_var_str);
+		hist_err("Couldn't find onmax or onchange variable: ", track_data_var_str);
 		return -EINVAL;
 	}
 
@@ -3457,39 +3758,26 @@ static int onmax_create(struct hist_trigger_data *hist_data,
 	if (!ref_field)
 		return -ENOMEM;
 
-	data->onmax.var = ref_field;
+	data->track_data.var_ref = ref_field;
 
-	data->fn = onmax_save;
-	data->onmax.max_var_ref_idx = var_ref_idx;
-	max_var = create_var(hist_data, file, "max", sizeof(u64), "u64");
-	if (IS_ERR(max_var)) {
-		hist_err("onmax: Couldn't create onmax variable: ", "max");
-		ret = PTR_ERR(max_var);
+	if (data->handler == HANDLER_ONMAX)
+		track_var = create_var(hist_data, file, "__max", sizeof(u64), "u64");
+	if (IS_ERR(track_var)) {
+		hist_err("Couldn't create onmax variable: ", "__max");
+		ret = PTR_ERR(track_var);
 		goto out;
 	}
-	data->onmax.max_var = max_var;
-
-	for (i = 0; i < data->n_params; i++) {
-		param = kstrdup(data->params[i], GFP_KERNEL);
-		if (!param) {
-			ret = -ENOMEM;
-			goto out;
-		}
-
-		field_var = create_target_field_var(hist_data, NULL, NULL, param);
-		if (IS_ERR(field_var)) {
-			hist_err("onmax: Couldn't create field variable: ", param);
-			ret = PTR_ERR(field_var);
-			kfree(param);
-			goto out;
-		}
-
-		hist_data->max_vars[hist_data->n_max_vars++] = field_var;
-		if (field_var->val->flags & HIST_FIELD_FL_STRING)
-			hist_data->n_max_var_str++;
 
-		kfree(param);
+	if (data->handler == HANDLER_ONCHANGE)
+		track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
+	if (IS_ERR(track_var)) {
+		hist_err("Couldn't create onchange variable: ", "__change");
+		ret = PTR_ERR(track_var);
+		goto out;
 	}
+	data->track_data.track_var = track_var;
+
+	ret = action_create(hist_data, data);
  out:
 	return ret;
 }
@@ -3497,14 +3785,18 @@ static int onmax_create(struct hist_trigger_data *hist_data,
 static int parse_action_params(char *params, struct action_data *data)
 {
 	char *param, *saved_param;
+	bool first_param = true;
 	int ret = 0;
 
 	while (params) {
-		if (data->n_params >= SYNTH_FIELDS_MAX)
+		if (data->n_params >= SYNTH_FIELDS_MAX) {
+			hist_err("Too many action params", "");
 			goto out;
+		}
 
 		param = strsep(&params, ",");
 		if (!param) {
+			hist_err("No action param found", "");
 			ret = -EINVAL;
 			goto out;
 		}
@@ -3522,86 +3814,164 @@ static int parse_action_params(char *params, struct action_data *data)
 			goto out;
 		}
 
+		if (first_param && data->use_trace_keyword) {
+			data->synth_event_name = saved_param;
+			first_param = false;
+			continue;
+		}
+		first_param = false;
+
 		data->params[data->n_params++] = saved_param;
 	}
  out:
 	return ret;
 }
 
-static struct action_data *onmax_parse(char *str)
+static int action_parse(char *str, struct action_data *data,
+			enum handler_id handler)
 {
-	char *onmax_fn_name, *onmax_var_str;
-	struct action_data *data;
-	int ret = -EINVAL;
-
-	data = kzalloc(sizeof(*data), GFP_KERNEL);
-	if (!data)
-		return ERR_PTR(-ENOMEM);
+	char *action_name;
+	int ret = 0;
 
-	onmax_var_str = strsep(&str, ")");
-	if (!onmax_var_str || !str) {
+	strsep(&str, ".");
+	if (!str) {
+		hist_err("action parsing: No action found", "");
 		ret = -EINVAL;
-		goto free;
+		goto out;
 	}
 
-	data->onmax.var_str = kstrdup(onmax_var_str, GFP_KERNEL);
-	if (!data->onmax.var_str) {
-		ret = -ENOMEM;
-		goto free;
+	action_name = strsep(&str, "(");
+	if (!action_name || !str) {
+		hist_err("action parsing: No action found", "");
+		ret = -EINVAL;
+		goto out;
 	}
 
-	strsep(&str, ".");
-	if (!str)
-		goto free;
-
-	onmax_fn_name = strsep(&str, "(");
-	if (!onmax_fn_name || !str)
-		goto free;
-
-	if (str_has_prefix(onmax_fn_name, "save")) {
+	if (str_has_prefix(action_name, "save")) {
 		char *params = strsep(&str, ")");
 
 		if (!params) {
+			hist_err("action parsing: No params found for %s", "save");
 			ret = -EINVAL;
-			goto free;
+			goto out;
 		}
 
 		ret = parse_action_params(params, data);
 		if (ret)
-			goto free;
-	} else
+			goto out;
+
+		if (handler == HANDLER_ONMAX)
+			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
+		else {
+			hist_err("action parsing: Handler doesn't support action: ", action_name);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		data->track_data.save_data = save_track_data_vars;
+		data->fn = ontrack_action;
+		data->action = ACTION_SAVE;
+	} else if (str_has_prefix(action_name, "snapshot")) {
+		char *params = strsep(&str, ")");
+
+		if (!str) {
+			hist_err("action parsing: No closing paren found: %s", params);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (handler == HANDLER_ONMAX)
+			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
+		else {
+			hist_err("action parsing: Handler doesn't support action: ", action_name);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		data->track_data.save_data = save_track_data_snapshot;
+		data->fn = ontrack_action;
+		data->action = ACTION_SNAPSHOT;
+	} else {
+		char *params = strsep(&str, ")");
+
+		if (str_has_prefix(action_name, "trace"))
+			data->use_trace_keyword = true;
+
+		if (params) {
+			ret = parse_action_params(params, data);
+			if (ret)
+				goto out;
+		}
+
+		if (handler == HANDLER_ONMAX)
+			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
+
+		if (handler != HANDLER_ONMATCH) {
+			data->track_data.save_data = action_trace;
+			data->fn = ontrack_action;
+		} else
+			data->fn = action_trace;
+
+		data->action = ACTION_TRACE;
+	}
+
+	data->action_name = kstrdup(action_name, GFP_KERNEL);
+	if (!data->action_name) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	data->handler = handler;
+ out:
+	return ret;
+}
+
+static struct action_data *track_data_parse(struct hist_trigger_data *hist_data,
+					    char *str, enum handler_id handler)
+{
+	struct action_data *data;
+	int ret = -EINVAL;
+	char *var_str;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	var_str = strsep(&str, ")");
+	if (!var_str || !str) {
+		ret = -EINVAL;
 		goto free;
+	}
 
-	data->onmax.fn_name = kstrdup(onmax_fn_name, GFP_KERNEL);
-	if (!data->onmax.fn_name) {
+	data->track_data.var_str = kstrdup(var_str, GFP_KERNEL);
+	if (!data->track_data.var_str) {
 		ret = -ENOMEM;
 		goto free;
 	}
+
+	ret = action_parse(str, data, handler);
+	if (ret)
+		goto free;
  out:
 	return data;
  free:
-	onmax_destroy(data);
+	track_data_destroy(hist_data, data);
 	data = ERR_PTR(ret);
 	goto out;
 }
 
 static void onmatch_destroy(struct action_data *data)
 {
-	unsigned int i;
-
-	lockdep_assert_held(&event_mutex);
-
-	kfree(data->onmatch.match_event);
-	kfree(data->onmatch.match_event_system);
-	kfree(data->onmatch.synth_event_name);
-
-	for (i = 0; i < data->n_params; i++)
-		kfree(data->params[i]);
+	kfree(data->match_data.event);
+	kfree(data->match_data.event_system);
 
-	if (data->onmatch.synth_event)
-		data->onmatch.synth_event->ref--;
-
-	kfree(data);
+	action_data_destroy(data);
 }
 
 static void destroy_field_var(struct field_var *field_var)
@@ -3651,8 +4021,9 @@ static int check_synth_field(struct synth_event *event,
 }
 
 static struct hist_field *
-onmatch_find_var(struct hist_trigger_data *hist_data, struct action_data *data,
-		 char *system, char *event, char *var)
+trace_action_find_var(struct hist_trigger_data *hist_data,
+		      struct action_data *data,
+		      char *system, char *event, char *var)
 {
 	struct hist_field *hist_field;
 
@@ -3660,24 +4031,24 @@ onmatch_find_var(struct hist_trigger_data *hist_data, struct action_data *data,
 
 	hist_field = find_target_event_var(hist_data, system, event, var);
 	if (!hist_field) {
-		if (!system) {
-			system = data->onmatch.match_event_system;
-			event = data->onmatch.match_event;
+		if (!system && data->handler == HANDLER_ONMATCH) {
+			system = data->match_data.event_system;
+			event = data->match_data.event;
 		}
 
 		hist_field = find_event_var(hist_data, system, event, var);
 	}
 
 	if (!hist_field)
-		hist_err_event("onmatch: Couldn't find onmatch param: $", system, event, var);
+		hist_err_event("trace action: Couldn't find param: $", system, event, var);
 
 	return hist_field;
 }
 
 static struct hist_field *
-onmatch_create_field_var(struct hist_trigger_data *hist_data,
-			 struct action_data *data, char *system,
-			 char *event, char *var)
+trace_action_create_field_var(struct hist_trigger_data *hist_data,
+			      struct action_data *data, char *system,
+			      char *event, char *var)
 {
 	struct hist_field *hist_field = NULL;
 	struct field_var *field_var;
@@ -3700,9 +4071,9 @@ onmatch_create_field_var(struct hist_trigger_data *hist_data,
 		 * looking for fields on the onmatch(system.event.xxx)
 		 * event.
 		 */
-		if (!system) {
-			system = data->onmatch.match_event_system;
-			event = data->onmatch.match_event;
+		if (!system && data->handler == HANDLER_ONMATCH) {
+			system = data->match_data.event_system;
+			event = data->match_data.event;
 		}
 
 		/*
@@ -3724,24 +4095,30 @@ onmatch_create_field_var(struct hist_trigger_data *hist_data,
 	goto out;
 }
 
-static int onmatch_create(struct hist_trigger_data *hist_data,
-			  struct trace_event_file *file,
-			  struct action_data *data)
+static int trace_action_create(struct hist_trigger_data *hist_data,
+			       struct action_data *data)
 {
 	char *event_name, *param, *system = NULL;
 	struct hist_field *hist_field, *var_ref;
 	unsigned int i, var_ref_idx;
 	unsigned int field_pos = 0;
 	struct synth_event *event;
+	char *synth_event_name;
 	int ret = 0;
 
 	lockdep_assert_held(&event_mutex);
 
-	event = find_synth_event(data->onmatch.synth_event_name);
+	if (data->use_trace_keyword)
+		synth_event_name = data->synth_event_name;
+	else
+		synth_event_name = data->action_name;
+
+	event = find_synth_event(synth_event_name);
 	if (!event) {
-		hist_err("onmatch: Couldn't find synthetic event: ", data->onmatch.synth_event_name);
+		hist_err("trace action: Couldn't find synthetic event: ", synth_event_name);
 		return -EINVAL;
 	}
+
 	event->ref++;
 
 	var_ref_idx = hist_data->n_var_refs;
@@ -3769,13 +4146,15 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
 		}
 
 		if (param[0] == '$')
-			hist_field = onmatch_find_var(hist_data, data, system,
-						      event_name, param);
+			hist_field = trace_action_find_var(hist_data, data,
+							   system, event_name,
+							   param);
 		else
-			hist_field = onmatch_create_field_var(hist_data, data,
-							      system,
-							      event_name,
-							      param);
+			hist_field = trace_action_create_field_var(hist_data,
+								   data,
+								   system,
+								   event_name,
+								   param);
 
 		if (!hist_field) {
 			kfree(p);
@@ -3797,7 +4176,7 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
 			continue;
 		}
 
-		hist_err_event("onmatch: Param type doesn't match synthetic event field type: ",
+		hist_err_event("trace action: Param type doesn't match synthetic event field type: ",
 			       system, event_name, param);
 		kfree(p);
 		ret = -EINVAL;
@@ -3805,14 +4184,13 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
 	}
 
 	if (field_pos != event->n_fields) {
-		hist_err("onmatch: Param count doesn't match synthetic event field count: ", event->name);
+		hist_err("trace action: Param count doesn't match synthetic event field count: ", event->name);
 		ret = -EINVAL;
 		goto err;
 	}
 
-	data->fn = action_trace;
-	data->onmatch.synth_event = event;
-	data->onmatch.var_ref_idx = var_ref_idx;
+	data->synth_event = event;
+	data->var_ref_idx = var_ref_idx;
  out:
 	return ret;
  err:
@@ -3821,10 +4199,75 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
 	goto out;
 }
 
+static int action_create(struct hist_trigger_data *hist_data,
+			 struct action_data *data)
+{
+	struct trace_event_file *file = hist_data->event_file;
+	struct track_data *track_data;
+	struct field_var *field_var;
+	unsigned int i;
+	char *param;
+	int ret = 0;
+
+	if (data->action == ACTION_TRACE)
+		return trace_action_create(hist_data, data);
+
+	if (data->action == ACTION_SNAPSHOT) {
+		track_data = track_data_alloc(hist_data->key_size, data, hist_data);
+		if (IS_ERR(track_data)) {
+			ret = PTR_ERR(track_data);
+			goto out;
+		}
+
+		ret = tracing_snapshot_cond_enable(file->tr, track_data,
+						   cond_snapshot_update);
+		if (ret)
+			track_data_free(track_data);
+
+		goto out;
+	}
+
+	if (data->action == ACTION_SAVE) {
+		if (hist_data->n_save_vars) {
+			ret = -EEXIST;
+			hist_err("save action: Can't have more than one save() action per hist", "");
+			goto out;
+		}
+
+		for (i = 0; i < data->n_params; i++) {
+			param = kstrdup(data->params[i], GFP_KERNEL);
+			if (!param) {
+				ret = -ENOMEM;
+				goto out;
+			}
+
+			field_var = create_target_field_var(hist_data, NULL, NULL, param);
+			if (IS_ERR(field_var)) {
+				hist_err("save action: Couldn't create field variable: ", param);
+				ret = PTR_ERR(field_var);
+				kfree(param);
+				goto out;
+			}
+
+			hist_data->save_vars[hist_data->n_save_vars++] = field_var;
+			if (field_var->val->flags & HIST_FIELD_FL_STRING)
+				hist_data->n_save_var_str++;
+			kfree(param);
+		}
+	}
+ out:
+	return ret;
+}
+
+static int onmatch_create(struct hist_trigger_data *hist_data,
+			  struct action_data *data)
+{
+	return action_create(hist_data, data);
+}
+
 static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
 {
 	char *match_event, *match_event_system;
-	char *synth_event_name, *params;
 	struct action_data *data;
 	int ret = -EINVAL;
 
@@ -3850,43 +4293,19 @@ static struct action_data *onmatch_parse(struct trace_array *tr, char *str)
 		goto free;
 	}
 
-	data->onmatch.match_event = kstrdup(match_event, GFP_KERNEL);
-	if (!data->onmatch.match_event) {
-		ret = -ENOMEM;
-		goto free;
-	}
-
-	data->onmatch.match_event_system = kstrdup(match_event_system, GFP_KERNEL);
-	if (!data->onmatch.match_event_system) {
+	data->match_data.event = kstrdup(match_event, GFP_KERNEL);
+	if (!data->match_data.event) {
 		ret = -ENOMEM;
 		goto free;
 	}
 
-	strsep(&str, ".");
-	if (!str) {
-		hist_err("onmatch: Missing . after onmatch(): ", str);
-		goto free;
-	}
-
-	synth_event_name = strsep(&str, "(");
-	if (!synth_event_name || !str) {
-		hist_err("onmatch: Missing opening paramlist paren: ", synth_event_name);
-		goto free;
-	}
-
-	data->onmatch.synth_event_name = kstrdup(synth_event_name, GFP_KERNEL);
-	if (!data->onmatch.synth_event_name) {
+	data->match_data.event_system = kstrdup(match_event_system, GFP_KERNEL);
+	if (!data->match_data.event_system) {
 		ret = -ENOMEM;
 		goto free;
 	}
 
-	params = strsep(&str, ")");
-	if (!params || !str || (str && strlen(str))) {
-		hist_err("onmatch: Missing closing paramlist paren: ", params);
-		goto free;
-	}
-
-	ret = parse_action_params(params, data);
+	ret = action_parse(str, data, HANDLER_ONMATCH);
 	if (ret)
 		goto free;
  out:
@@ -4326,10 +4745,11 @@ static void destroy_actions(struct hist_trigger_data *hist_data)
 	for (i = 0; i < hist_data->n_actions; i++) {
 		struct action_data *data = hist_data->actions[i];
 
-		if (data->fn == action_trace)
+		if (data->handler == HANDLER_ONMATCH)
 			onmatch_destroy(data);
-		else if (data->fn == onmax_save)
-			onmax_destroy(data);
+		else if (data->handler == HANDLER_ONMAX ||
+			 data->handler == HANDLER_ONCHANGE)
+			track_data_destroy(hist_data, data);
 		else
 			kfree(data);
 	}
@@ -4355,16 +4775,24 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 				ret = PTR_ERR(data);
 				break;
 			}
-			data->fn = action_trace;
 		} else if ((len = str_has_prefix(str, "onmax("))) {
 			char *action_str = str + len;
 
-			data = onmax_parse(action_str);
+			data = track_data_parse(hist_data, action_str,
+						HANDLER_ONMAX);
+			if (IS_ERR(data)) {
+				ret = PTR_ERR(data);
+				break;
+			}
+		} else if ((len = str_has_prefix(str, "onchange("))) {
+			char *action_str = str + len;
+
+			data = track_data_parse(hist_data, action_str,
+						HANDLER_ONCHANGE);
 			if (IS_ERR(data)) {
 				ret = PTR_ERR(data);
 				break;
 			}
-			data->fn = onmax_save;
 		} else {
 			ret = -EINVAL;
 			break;
@@ -4376,8 +4804,7 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 	return ret;
 }
 
-static int create_actions(struct hist_trigger_data *hist_data,
-			  struct trace_event_file *file)
+static int create_actions(struct hist_trigger_data *hist_data)
 {
 	struct action_data *data;
 	unsigned int i;
@@ -4386,14 +4813,18 @@ static int create_actions(struct hist_trigger_data *hist_data,
 	for (i = 0; i < hist_data->attrs->n_actions; i++) {
 		data = hist_data->actions[i];
 
-		if (data->fn == action_trace) {
-			ret = onmatch_create(hist_data, file, data);
+		if (data->handler == HANDLER_ONMATCH) {
+			ret = onmatch_create(hist_data, data);
 			if (ret)
-				return ret;
-		} else if (data->fn == onmax_save) {
-			ret = onmax_create(hist_data, data);
+				break;
+		} else if (data->handler == HANDLER_ONMAX ||
+			   data->handler == HANDLER_ONCHANGE) {
+			ret = track_data_create(hist_data, data);
 			if (ret)
-				return ret;
+				break;
+		} else {
+			ret = -EINVAL;
+			break;
 		}
 	}
 
@@ -4409,26 +4840,51 @@ static void print_actions(struct seq_file *m,
 	for (i = 0; i < hist_data->n_actions; i++) {
 		struct action_data *data = hist_data->actions[i];
 
-		if (data->fn == onmax_save)
-			onmax_print(m, hist_data, elt, data);
+		if (data->action == ACTION_SNAPSHOT)
+			continue;
+
+		if (data->handler == HANDLER_ONMAX ||
+		    data->handler == HANDLER_ONCHANGE)
+			track_data_print(m, hist_data, elt, data);
 	}
 }
 
-static void print_onmax_spec(struct seq_file *m,
-			     struct hist_trigger_data *hist_data,
-			     struct action_data *data)
+static void print_action_spec(struct seq_file *m,
+			      struct hist_trigger_data *hist_data,
+			      struct action_data *data)
 {
 	unsigned int i;
 
-	seq_puts(m, ":onmax(");
-	seq_printf(m, "%s", data->onmax.var_str);
-	seq_printf(m, ").%s(", data->onmax.fn_name);
-
-	for (i = 0; i < hist_data->n_max_vars; i++) {
-		seq_printf(m, "%s", hist_data->max_vars[i]->var->var.name);
-		if (i < hist_data->n_max_vars - 1)
-			seq_puts(m, ",");
+	if (data->action == ACTION_SAVE) {
+		for (i = 0; i < hist_data->n_save_vars; i++) {
+			seq_printf(m, "%s", hist_data->save_vars[i]->var->var.name);
+			if (i < hist_data->n_save_vars - 1)
+				seq_puts(m, ",");
+		}
+	} else if (data->action == ACTION_TRACE) {
+		if (data->use_trace_keyword)
+			seq_printf(m, "%s", data->synth_event_name);
+		for (i = 0; i < data->n_params; i++) {
+			if (i || data->use_trace_keyword)
+				seq_puts(m, ",");
+			seq_printf(m, "%s", data->params[i]);
+		}
 	}
+}
+
+static void print_track_data_spec(struct seq_file *m,
+				  struct hist_trigger_data *hist_data,
+				  struct action_data *data)
+{
+	if (data->handler == HANDLER_ONMAX)
+		seq_puts(m, ":onmax(");
+	else if (data->handler == HANDLER_ONCHANGE)
+		seq_puts(m, ":onchange(");
+	seq_printf(m, "%s", data->track_data.var_str);
+	seq_printf(m, ").%s(", data->action_name);
+
+	print_action_spec(m, hist_data, data);
+
 	seq_puts(m, ")");
 }
 
@@ -4436,18 +4892,12 @@ static void print_onmatch_spec(struct seq_file *m,
 			       struct hist_trigger_data *hist_data,
 			       struct action_data *data)
 {
-	unsigned int i;
-
-	seq_printf(m, ":onmatch(%s.%s).", data->onmatch.match_event_system,
-		   data->onmatch.match_event);
+	seq_printf(m, ":onmatch(%s.%s).", data->match_data.event_system,
+		   data->match_data.event);
 
-	seq_printf(m, "%s(", data->onmatch.synth_event->name);
+	seq_printf(m, "%s(", data->action_name);
 
-	for (i = 0; i < data->n_params; i++) {
-		if (i)
-			seq_puts(m, ",");
-		seq_printf(m, "%s", data->params[i]);
-	}
+	print_action_spec(m, hist_data, data);
 
 	seq_puts(m, ")");
 }
@@ -4463,8 +4913,11 @@ static bool actions_match(struct hist_trigger_data *hist_data,
 	for (i = 0; i < hist_data->n_actions; i++) {
 		struct action_data *data = hist_data->actions[i];
 		struct action_data *data_test = hist_data_test->actions[i];
+		char *action_name, *action_name_test;
 
-		if (data->fn != data_test->fn)
+		if (data->handler != data_test->handler)
+			return false;
+		if (data->action != data_test->action)
 			return false;
 
 		if (data->n_params != data_test->n_params)
@@ -4475,22 +4928,30 @@ static bool actions_match(struct hist_trigger_data *hist_data,
 				return false;
 		}
 
-		if (data->fn == action_trace) {
-			if (strcmp(data->onmatch.synth_event_name,
-				   data_test->onmatch.synth_event_name) != 0)
-				return false;
-			if (strcmp(data->onmatch.match_event_system,
-				   data_test->onmatch.match_event_system) != 0)
-				return false;
-			if (strcmp(data->onmatch.match_event,
-				   data_test->onmatch.match_event) != 0)
+		if (data->use_trace_keyword)
+			action_name = data->synth_event_name;
+		else
+			action_name = data->action_name;
+
+		if (data_test->use_trace_keyword)
+			action_name_test = data_test->synth_event_name;
+		else
+			action_name_test = data_test->action_name;
+
+		if (strcmp(action_name, action_name_test) != 0)
+			return false;
+
+		if (data->handler == HANDLER_ONMATCH) {
+			if (strcmp(data->match_data.event_system,
+				   data_test->match_data.event_system) != 0)
 				return false;
-		} else if (data->fn == onmax_save) {
-			if (strcmp(data->onmax.var_str,
-				   data_test->onmax.var_str) != 0)
+			if (strcmp(data->match_data.event,
+				   data_test->match_data.event) != 0)
 				return false;
-			if (strcmp(data->onmax.fn_name,
-				   data_test->onmax.fn_name) != 0)
+		} else if (data->handler == HANDLER_ONMAX ||
+			   data->handler == HANDLER_ONCHANGE) {
+			if (strcmp(data->track_data.var_str,
+				   data_test->track_data.var_str) != 0)
 				return false;
 		}
 	}
@@ -4507,10 +4968,11 @@ static void print_actions_spec(struct seq_file *m,
 	for (i = 0; i < hist_data->n_actions; i++) {
 		struct action_data *data = hist_data->actions[i];
 
-		if (data->fn == action_trace)
+		if (data->handler == HANDLER_ONMATCH)
 			print_onmatch_spec(m, hist_data, data);
-		else if (data->fn == onmax_save)
-			print_onmax_spec(m, hist_data, data);
+		else if (data->handler == HANDLER_ONMAX ||
+			 data->handler == HANDLER_ONCHANGE)
+			print_track_data_spec(m, hist_data, data);
 	}
 }
 
@@ -4695,22 +5157,24 @@ static inline void add_to_key(char *compound_key, void *key,
 		/* ensure NULL-termination */
 		if (size > key_field->size - 1)
 			size = key_field->size - 1;
-	}
 
-	memcpy(compound_key + key_field->offset, key, size);
+		strncpy(compound_key + key_field->offset, (char *)key, size);
+	} else
+		memcpy(compound_key + key_field->offset, key, size);
 }
 
 static void
 hist_trigger_actions(struct hist_trigger_data *hist_data,
 		     struct tracing_map_elt *elt, void *rec,
-		     struct ring_buffer_event *rbe, u64 *var_ref_vals)
+		     struct ring_buffer_event *rbe, void *key,
+		     u64 *var_ref_vals)
 {
 	struct action_data *data;
 	unsigned int i;
 
 	for (i = 0; i < hist_data->n_actions; i++) {
 		data = hist_data->actions[i];
-		data->fn(hist_data, elt, rec, rbe, data, var_ref_vals);
+		data->fn(hist_data, elt, rec, rbe, key, data, var_ref_vals);
 	}
 }
 
@@ -4771,7 +5235,7 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec,
 	hist_trigger_elt_update(hist_data, elt, rec, rbe, var_ref_vals);
 
 	if (resolve_var_refs(hist_data, key, var_ref_vals, true))
-		hist_trigger_actions(hist_data, elt, rec, rbe, var_ref_vals);
+		hist_trigger_actions(hist_data, elt, rec, rbe, key, var_ref_vals);
 }
 
 static void hist_trigger_stacktrace_print(struct seq_file *m,
@@ -4792,10 +5256,10 @@ static void hist_trigger_stacktrace_print(struct seq_file *m,
 	}
 }
 
-static void
-hist_trigger_entry_print(struct seq_file *m,
-			 struct hist_trigger_data *hist_data, void *key,
-			 struct tracing_map_elt *elt)
+static void hist_trigger_print_key(struct seq_file *m,
+				   struct hist_trigger_data *hist_data,
+				   void *key,
+				   struct tracing_map_elt *elt)
 {
 	struct hist_field *key_field;
 	char str[KSYM_SYMBOL_LEN];
@@ -4871,6 +5335,17 @@ hist_trigger_entry_print(struct seq_file *m,
 		seq_puts(m, " ");
 
 	seq_puts(m, "}");
+}
+
+static void hist_trigger_entry_print(struct seq_file *m,
+				     struct hist_trigger_data *hist_data,
+				     void *key,
+				     struct tracing_map_elt *elt)
+{
+	const char *field_name;
+	unsigned int i;
+
+	hist_trigger_print_key(m, hist_data, key, elt);
 
 	seq_printf(m, " hitcount: %10llu",
 		   tracing_map_read_sum(elt, HITCOUNT_IDX));
@@ -4937,6 +5412,8 @@ static void hist_trigger_show(struct seq_file *m,
 	if (n_entries < 0)
 		n_entries = 0;
 
+	track_data_snapshot_print(m, hist_data);
+
 	seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
 		   (u64)atomic64_read(&hist_data->map->hits),
 		   n_entries, (u64)atomic64_read(&hist_data->map->drops));
@@ -5683,7 +6160,7 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
 	if (has_hist_vars(hist_data))
 		save_hist_vars(hist_data);
 
-	ret = create_actions(hist_data, file);
+	ret = create_actions(hist_data);
 	if (ret)
 		goto out_unreg;
 
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index c2af1560e856..69ebf3c2f1b5 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -380,6 +380,7 @@ static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 {
 	trace_seq_putc(s, ' ');
 	trace_print_lat_fmt(s, entry);
+	trace_seq_puts(s, " | ");
 }
 
 /* If the pid changed since the last trace, output this event */
@@ -501,6 +502,17 @@ static void print_graph_abs_time(u64 t, struct trace_seq *s)
 }
 
 static void
+print_graph_rel_time(struct trace_iterator *iter, struct trace_seq *s)
+{
+	unsigned long long usecs;
+
+	usecs = iter->ts - iter->trace_buffer->time_start;
+	do_div(usecs, NSEC_PER_USEC);
+
+	trace_seq_printf(s, "%9llu us |  ", usecs);
+}
+
+static void
 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 		enum trace_type type, int cpu, pid_t pid, u32 flags)
 {
@@ -517,6 +529,10 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 		if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 			print_graph_abs_time(iter->ts, s);
 
+		/* Relative time */
+		if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+			print_graph_rel_time(iter, s);
+
 		/* Cpu */
 		if (flags & TRACE_GRAPH_PRINT_CPU)
 			print_graph_cpu(s, cpu);
@@ -725,6 +741,10 @@ print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 		print_graph_abs_time(iter->ts, s);
 
+	/* Relative time */
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		print_graph_rel_time(iter, s);
+
 	/* Cpu */
 	if (flags & TRACE_GRAPH_PRINT_CPU)
 		print_graph_cpu(s, cpu);
@@ -1101,6 +1121,8 @@ static void print_lat_header(struct seq_file *s, u32 flags)
 
 	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 		size += 16;
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		size += 16;
 	if (flags & TRACE_GRAPH_PRINT_CPU)
 		size += 4;
 	if (flags & TRACE_GRAPH_PRINT_PROC)
@@ -1125,12 +1147,14 @@ static void __print_graph_headers_flags(struct trace_array *tr,
 	seq_putc(s, '#');
 	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 		seq_puts(s, "     TIME       ");
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		seq_puts(s, "   REL TIME     ");
 	if (flags & TRACE_GRAPH_PRINT_CPU)
 		seq_puts(s, " CPU");
 	if (flags & TRACE_GRAPH_PRINT_PROC)
 		seq_puts(s, "  TASK/PID       ");
 	if (lat)
-		seq_puts(s, "||||");
+		seq_puts(s, "||||   ");
 	if (flags & TRACE_GRAPH_PRINT_DURATION)
 		seq_puts(s, "  DURATION   ");
 	seq_puts(s, "               FUNCTION CALLS\n");
@@ -1139,12 +1163,14 @@ static void __print_graph_headers_flags(struct trace_array *tr,
 	seq_putc(s, '#');
 	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
 		seq_puts(s, "      |         ");
+	if (flags & TRACE_GRAPH_PRINT_REL_TIME)
+		seq_puts(s, "      |         ");
 	if (flags & TRACE_GRAPH_PRINT_CPU)
 		seq_puts(s, " |  ");
 	if (flags & TRACE_GRAPH_PRINT_PROC)
 		seq_puts(s, "   |    |        ");
 	if (lat)
-		seq_puts(s, "||||");
+		seq_puts(s, "||||   ");
 	if (flags & TRACE_GRAPH_PRINT_DURATION)
 		seq_puts(s, "   |   |      ");
 	seq_puts(s, "               |   |   |   |\n");
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index d42a473b8240..a745b0cee5d3 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -239,7 +239,7 @@ static void irqsoff_trace_close(struct trace_iterator *iter)
 
 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_CPU | \
 			    TRACE_GRAPH_PRINT_PROC | \
-			    TRACE_GRAPH_PRINT_ABS_TIME | \
+			    TRACE_GRAPH_PRINT_REL_TIME | \
 			    TRACE_GRAPH_PRINT_DURATION)
 
 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 9962cb5da8ac..89da34b326e3 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -300,6 +300,7 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
 
 	case '+':	/* deref memory */
 		arg++;	/* Skip '+', because kstrtol() rejects it. */
+		/* fall through */
 	case '-':
 		tmp = strchr(arg, '(');
 		if (!tmp)
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 4ea7e6845efb..743b2b520d34 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -180,8 +180,11 @@ static void wakeup_trace_close(struct trace_iterator *iter)
 }
 
 #define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \
-			    TRACE_GRAPH_PRINT_ABS_TIME | \
-			    TRACE_GRAPH_PRINT_DURATION)
+			    TRACE_GRAPH_PRINT_CPU |  \
+			    TRACE_GRAPH_PRINT_REL_TIME | \
+			    TRACE_GRAPH_PRINT_DURATION | \
+			    TRACE_GRAPH_PRINT_OVERHEAD | \
+			    TRACE_GRAPH_PRINT_IRQS)
 
 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
 {
@@ -472,6 +475,7 @@ probe_wakeup_sched_switch(void *ignore, bool preempt,
 
 	__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
 	tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
+	__trace_stack(wakeup_trace, flags, 0, pc);
 
 	T0 = data->preempt_timestamp;
 	T1 = ftrace_now(cpu);
@@ -482,7 +486,7 @@ probe_wakeup_sched_switch(void *ignore, bool preempt,
 
 	if (likely(!is_tracing_stopped())) {
 		wakeup_trace->max_latency = delta;
-		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
+		update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu, NULL);
 	}
 
 out_unlock:
@@ -583,6 +587,7 @@ probe_wakeup(void *ignore, struct task_struct *p)
 	data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu);
 	data->preempt_timestamp = ftrace_now(cpu);
 	tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
+	__trace_stack(wakeup_trace, flags, 0, pc);
 
 	/*
 	 * We must be careful in using CALLER_ADDR2. But since wake_up
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-action-hist-xfail.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-action-hist-xfail.tc
new file mode 100644
index 000000000000..1221240f8cf6
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-action-hist-xfail.tc
@@ -0,0 +1,30 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test inter-event histogram trigger expected fail actions
+
+fail() { #msg
+    echo $1
+    exit_fail
+}
+
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f snapshot ]; then
+    echo "snapshot is not supported"
+    exit_unsupported
+fi
+
+grep -q "snapshot()" README || exit_unsupported # version issue
+
+echo "Test expected snapshot action failure"
+
+echo 'hist:keys=comm:onmatch(sched.sched_wakeup).snapshot()' >> /sys/kernel/debug/tracing/events/sched/sched_waking/trigger && exit_fail
+
+echo "Test expected save action failure"
+
+echo 'hist:keys=comm:onmatch(sched.sched_wakeup).save(comm,prio)' >> /sys/kernel/debug/tracing/events/sched/sched_waking/trigger && exit_fail
+
+exit_xfail
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-extended-error-support.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-extended-error-support.tc
index 401104344593..9912616a8672 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-extended-error-support.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-extended-error-support.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test extended error support
 
 
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc
index f59b2a9a1f22..77be6e1f6e7b 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test field variable support
 
 fail() { #msg
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-inter-event-combined-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-inter-event-combined-hist.tc
index 524d9ce361e2..f3eb8aacec0e 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-inter-event-combined-hist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-inter-event-combined-hist.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test inter-event combined histogram trigger
 
 fail() { #msg
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-multi-actions-accept.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-multi-actions-accept.tc
index 4ddc546771b5..d281f056f980 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-multi-actions-accept.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-multi-actions-accept.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test multiple actions on hist trigger
 
 fail() { #msg
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onchange-action-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onchange-action-hist.tc
new file mode 100644
index 000000000000..064a284e4e75
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onchange-action-hist.tc
@@ -0,0 +1,28 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test inter-event histogram trigger onchange action
+
+fail() { #msg
+    echo $1
+    exit_fail
+}
+
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+grep -q "onchange(var)" README || exit_unsupported # version issue
+
+echo "Test onchange action"
+
+echo 'hist:keys=comm:newprio=prio:onchange($newprio).save(comm,prio) if comm=="ping"' >> /sys/kernel/debug/tracing/events/sched/sched_waking/trigger
+
+ping $LOCALHOST -c 3
+nice -n 1 ping $LOCALHOST -c 3
+
+if ! grep -q "changed:" events/sched/sched_waking/hist; then
+    fail "Failed to create onchange action inter-event histogram"
+fi
+
+exit 0
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-action-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-action-hist.tc
index 39fb65b0cd9f..a708f0e7858a 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-action-hist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-action-hist.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test inter-event histogram trigger onmatch action
 
 fail() { #msg
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-onmax-action-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-onmax-action-hist.tc
index 81ab3939c96a..dfce6932d8be 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-onmax-action-hist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmatch-onmax-action-hist.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test inter-event histogram trigger onmatch-onmax action
 
 fail() { #msg
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmax-action-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmax-action-hist.tc
index 1180ab5f0845..0035995c2194 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmax-action-hist.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-onmax-action-hist.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test inter-event histogram trigger onmax action
 
 fail() { #msg
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-snapshot-action-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-snapshot-action-hist.tc
new file mode 100644
index 000000000000..18fff69fc433
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-snapshot-action-hist.tc
@@ -0,0 +1,43 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test inter-event histogram trigger snapshot action
+
+fail() { #msg
+    echo $1
+    exit_fail
+}
+
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f snapshot ]; then
+    echo "snapshot is not supported"
+    exit_unsupported
+fi
+
+grep -q "onchange(var)" README || exit_unsupported # version issue
+
+grep -q "snapshot()" README || exit_unsupported # version issue
+
+echo "Test snapshot action"
+
+echo 1 > /sys/kernel/debug/tracing/events/sched/enable
+
+echo 'hist:keys=comm:newprio=prio:onchange($newprio).save(comm,prio):onchange($newprio).snapshot() if comm=="ping"' >> /sys/kernel/debug/tracing/events/sched/sched_waking/trigger
+
+ping $LOCALHOST -c 3
+nice -n 1 ping $LOCALHOST -c 3
+
+echo 0 > tracing_on
+
+if ! grep -q "changed:" events/sched/sched_waking/hist; then
+    fail "Failed to create onchange action inter-event histogram"
+fi
+
+if ! grep -q "comm=ping" snapshot; then
+    fail "Failed to create snapshot action inter-event histogram"
+fi
+
+exit 0
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
index 41128219231a..df44b14724a4 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-synthetic-event-createremove.tc
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 # description: event trigger - test synthetic event create remove
 
 fail() { #msg
diff --git a/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-trace-action-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-trace-action-hist.tc
new file mode 100644
index 000000000000..8021d60aafec
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-trace-action-hist.tc
@@ -0,0 +1,42 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: event trigger - test inter-event histogram trigger trace action
+
+fail() { #msg
+    echo $1
+    exit_fail
+}
+
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f synthetic_events ]; then
+    echo "synthetic event is not supported"
+    exit_unsupported
+fi
+
+grep -q "trace(<synthetic_event>" README || exit_unsupported # version issue
+
+echo "Test create synthetic event"
+
+echo 'wakeup_latency  u64 lat pid_t pid char comm[16]' > synthetic_events
+if [ ! -d events/synthetic/wakeup_latency ]; then
+    fail "Failed to create wakeup_latency synthetic event"
+fi
+
+echo "Test create histogram for synthetic event using trace action"
+echo "Test histogram variables,simple expression support and trace action"
+
+echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="ping"' > events/sched/sched_wakeup/trigger
+echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_wakeup).trace(wakeup_latency,$wakeup_lat,next_pid,next_comm) if next_comm=="ping"' > events/sched/sched_switch/trigger
+echo 'hist:keys=comm,pid,lat:wakeup_lat=lat:sort=lat' > events/synthetic/wakeup_latency/trigger
+
+ping $LOCALHOST -c 5
+
+if ! grep -q "ping" events/synthetic/wakeup_latency/hist; then
+    fail "Failed to create trace action inter-event histogram"
+fi
+
+exit 0