| Commit message (Collapse) | Author | Age | Files | Lines |
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Fix this build error:
kernel/irq/internals.h:440:20: error: inlining failed in call to always_inline
'irq_domain_debugfs_init': function body not available
kernel/irq/debugfs.c:202:2: note: called from here
irq_domain_debugfs_init(root_dir);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.LFD.2.20.1707041124000.1712@schleppi
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS updates from Thomas Gleixner:
"The RAS updates for the 4.13 merge window:
- Cleanup of the MCE injection facility (Borsilav Petkov)
- Rework of the AMD/SMCA handling (Yazen Ghannam)
- Enhancements for ACPI/APEI to handle new notitication types (Shiju
Jose)
- atomic_t to refcount_t conversion (Elena Reshetova)
- A few fixes and enhancements all over the place"
* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
RAS/CEC: Check the correct variable in the debugfs error handling
x86/mce: Always save severity in machine_check_poll()
x86/MCE, xen/mcelog: Make /dev/mcelog registration messages more precise
x86/mce: Update bootlog description to reflect behavior on AMD
x86/mce: Don't disable MCA banks when offlining a CPU on AMD
x86/mce/mce-inject: Preset the MCE injection struct
x86/mce: Clean up include files
x86/mce: Get rid of register_mce_write_callback()
x86/mce: Merge mce_amd_inj into mce-inject
x86/mce/AMD: Use saved threshold block info in interrupt handler
x86/mce/AMD: Use msr_stat when clearing MCA_STATUS
x86/mce/AMD: Carve out SMCA bank configuration
x86/mce/AMD: Redo error logging from APIC LVT interrupt handlers
x86/mce: Convert threshold_bank.cpus from atomic_t to refcount_t
RAS: Make local function parse_ras_param() static
ACPI/APEI: Handle GSIV and GPIO notification types
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Check the correct variable when handling a potential error from
debugfs_create_file(). Most likely a copy-paste botch.
[ Rewrite commit message. ]
Fixes: 011d82611172 ("RAS: Add a Corrected Errors Collector")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170623062440.6726-1-christophe.jaillet@wanadoo.fr
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The MCE severity gives a hint as to how to handle the error. The
notifier blocks can then use the severity to decide on an action.
It's not necessary for machine_check_poll() to filter errors for
the notifier chain, since each block will check its own set of
conditions before handling an error.
Also, there isn't any urgency for machine_check_poll() to make decisions
based on severity like in do_machine_check().
If we can assume that a severity is set then we can use it in more
notifier blocks. For example, the CEC block could check for a "KEEP"
severity rather than checking bits in the status. This isn't possible
now since the severity is not set except for "DEFFRRED/UCNA" errors with
a valid address.
Save the severity since we have it, and let the notifier blocks decide
if they want to do anything.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1498074402-98633-1-git-send-email-Yazen.Ghannam@amd.com
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When running under Xen as dom0, /dev/mcelog is being provided by Xen
instead of the normal mcelog character device of the MCE core. Convert
an error message being issued by the MCE core in this case to an
informative message that Xen has registered the device.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170614084059.19294-1-jgross@suse.com
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The bootlog option is only disabled by default on AMD Fam10h and older
systems.
Update bootlog description to say this. Change the family value to hex
to avoid confusion.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170613162835.30750-9-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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AMD systems have non-core, shared MCA banks within a die. These banks
are controlled by a master CPU per die. If this CPU is offlined then all
the shared banks are disabled in addition to the CPU's core banks.
Also, Fam17h systems may have SMT enabled. The MCA_CTL register is shared
between SMT thread siblings. If a CPU is offlined then all its sibling's
MCA banks are also disabled.
Extend the existing vendor check to AMD too.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
[ Fix up comment. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170613162835.30750-8-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Populate the MCE injection struct before doing initial injection so that
values which don't change have sane defaults.
Tested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20170613162835.30750-7-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Not really needed.
Tested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20170613162835.30750-6-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Make the mcelog call a notifier which lands in the injector module and
does the injection. This allows for mce-inject to be a normal kernel
module now.
Tested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20170613162835.30750-5-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Reuse mce_amd_inj's debugfs interface so that mce-inject can
benefit from it too. The old functionality is still preserved under
CONFIG_X86_MCELOG_LEGACY.
Tested-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20170613162835.30750-4-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In the amd_threshold_interrupt() handler, we loop through every possible
block in each bank and rediscover the block's address and if it's valid,
e.g. valid, counter present and not locked.
However, we already have the address saved in the threshold blocks list
for each CPU and bank. The list only contains blocks that have passed
all the valid checks.
Besides the redundancy, there's also a smp_call_function* in
get_block_address() which causes a warning when servicing the interrupt:
WARNING: CPU: 0 PID: 0 at kernel/smp.c:281 smp_call_function_single+0xdd/0xf0
...
Call Trace:
<IRQ>
rdmsr_safe_on_cpu()
get_block_address.isra.2()
amd_threshold_interrupt()
smp_threshold_interrupt()
threshold_interrupt()
because we do get called in an interrupt handler *with* interrupts
disabled, which can result in a deadlock.
Drop the redundant valid checks and move the overflow check, logging and
block reset into a separate function.
Check the first block then iterate over the rest. This procedure is
needed since the first block is used as the head of the list.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170613162835.30750-3-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The value of MCA_STATUS is used as the MSR when clearing MCA_STATUS.
This may cause the following warning:
unchecked MSR access error: WRMSR to 0x11b (tried to write 0x0000000000000000)
Call Trace:
<IRQ>
smp_threshold_interrupt()
threshold_interrupt()
Use msr_stat instead which has the MSR address.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Fixes: 37d43acfd79f ("x86/mce/AMD: Redo error logging from APIC LVT interrupt handlers")
Link: http://lkml.kernel.org/r/20170613162835.30750-2-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Scalable MCA systems have a new MCA_CONFIG register that we use to
configure each bank. We currently use this when we set up thresholding.
However, this is logically separate.
Group all SMCA-related initialization into a single function.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1493147772-2721-2-git-send-email-Yazen.Ghannam@amd.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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We have support for the new SMCA MCA_DE{STAT,ADDR} registers in Linux.
So we've used these registers in place of MCA_{STATUS,ADDR} on SMCA
systems.
However, the guidance for current SMCA implementations of is to continue
using MCA_{STATUS,ADDR} and to use MCA_DE{STAT,ADDR} only if a Deferred
error was not found in the former registers. If we logged a Deferred
error in MCA_STATUS then we should also clear MCA_DESTAT. This also
means we shouldn't clear MCA_CONFIG[LogDeferredInMcaStat].
Rework __log_error() to only log an error and add helpers for the
different error types being logged from the corresponding interrupt
handlers.
Boris: carve out common functionality into a _log_error_bank(). Cleanup
comments, check MCi_STATUS bits before reading MSRs. Streamline flow.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1493147772-2721-1-git-send-email-Yazen.Ghannam@amd.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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The refcount_t type and corresponding API should be used instead
of atomic_t when the variable is used as a reference counter. This
allows to avoid accidental refcounter overflows that might lead to
use-after-free situations.
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1492695536-5947-1-git-send-email-elena.reshetova@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Make parse_ras_param() static as it is used locally only.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170516161034.2973-1-weiyj.lk@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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System Controller Interrupts are received by ACPI's error device, which
in turn notifies the GHES code. The same is true of APEI's GSIV and
GPIO notification types. Add support for GSIV and GPIO sharing the SCI
register/unregister/notifier code. Rename the list and notifier to show
this is no longer just SCI, but anything from the Hardware Error Device.
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
[ Rewrite commit log. ]
Signed-off-by: James Morse <james.morse@arm.com>
[ Some small cleanups ontop. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Tyler Baicar <tbaicar@codeaurora.org>
Reviewed-by: James Morse <james.morse@arm.com>
Link: http://lkml.kernel.org/r/86258A5CC0A3704780874CF6004BA8A62E695201@FRAEML521-MBX.china.huawei.com
Cc: "Guohanjun (Hanjun Guo)" <guohanjun@huawei.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: "Zhengqiang (turing)" <zhengqiang10@huawei.com>
Cc: "fu.wei@linaro.org" <fu.wei@linaro.org>
Cc: "xuwei (O)" <xuwei5@hisilicon.com>
Cc: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Cc: Geliang Tang <geliangtang@gmail.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Punit Agrawal <punit.agrawal@arm.com>
Cc: linux-acpi@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP hotplug updates from Thomas Gleixner:
"This update is primarily a cleanup of the CPU hotplug locking code.
The hotplug locking mechanism is an open coded RWSEM, which allows
recursive locking. The main problem with that is the recursive nature
as it evades the full lockdep coverage and hides potential deadlocks.
The rework replaces the open coded RWSEM with a percpu RWSEM and
establishes full lockdep coverage that way.
The bulk of the changes fix up recursive locking issues and address
the now fully reported potential deadlocks all over the place. Some of
these deadlocks have been observed in the RT tree, but on mainline the
probability was low enough to hide them away."
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
cpu/hotplug: Constify attribute_group structures
powerpc: Only obtain cpu_hotplug_lock if called by rtasd
ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init
cpu/hotplug: Remove unused check_for_tasks() function
perf/core: Don't release cred_guard_mutex if not taken
cpuhotplug: Link lock stacks for hotplug callbacks
acpi/processor: Prevent cpu hotplug deadlock
sched: Provide is_percpu_thread() helper
cpu/hotplug: Convert hotplug locking to percpu rwsem
s390: Prevent hotplug rwsem recursion
arm: Prevent hotplug rwsem recursion
arm64: Prevent cpu hotplug rwsem recursion
kprobes: Cure hotplug lock ordering issues
jump_label: Reorder hotplug lock and jump_label_lock
perf/tracing/cpuhotplug: Fix locking order
ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus()
PCI: Replace the racy recursion prevention
PCI: Use cpu_hotplug_disable() instead of get_online_cpus()
perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode()
x86/perf: Drop EXPORT of perf_check_microcode
...
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attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group.
So mark the non-const structs as const:
File size before:
text data bss dec hex filename
12582 15361 20 27963 6d3b kernel/cpu.o
File size After adding 'const':
text data bss dec hex filename
12710 15265 20 27995 6d5b kernel/cpu.o
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: anna-maria@linutronix.de
Cc: bigeasy@linutronix.de
Cc: boris.ostrovsky@oracle.com
Cc: rcochran@linutronix.de
Link: http://lkml.kernel.org/r/f9079e94e12b36d245e7adbf67d312bc5d0250c6.1498737970.git.arvind.yadav.cs@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Calling arch_update_cpu_topology from a CPU hotplug state machine callback
hits a deadlock because the function tries to get a read lock on
cpu_hotplug_lock while the state machine still holds a write lock on it.
Since all callers of arch_update_cpu_topology except rtasd already hold
cpu_hotplug_lock, this patch changes the function to use
stop_machine_cpuslocked and creates a separate function for rtasd which
still tries to obtain the lock.
Michael Bringmann investigated the bug and provided a detailed analysis
of the deadlock on this previous RFC for an alternate solution:
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michael Bringmann <mwb@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1497996510-4032-1-git-send-email-bauerman@linux.vnet.ibm.com
Link: https://patchwork.ozlabs.org/patch/771293/
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Recent change to use cpuhp_setup_state_cpuslocked() with commit
fe2a5cd8aa03 ("ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked()")
missed to change the related paired cpuhp_remove_state_nocalls_cpuslocked().
Now if arch_hw_breakpoint_init() fails, we get "WARNING: possible recursive
locking detected" on the exit path.
Fixes: fe2a5cd8aa03 ("ARM/hw_breakpoint: Use cpuhp_setup_state_cpuslocked()")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-omap@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170616082238.15553-1-tony@atomide.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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clang -Wunused-function found one remaining function that was
apparently meant to be removed in a recent code cleanup:
kernel/cpu.c:565:20: warning: unused function 'check_for_tasks' [-Wunused-function]
Sebastian explained: The function became unused unintentionally, but there
is already a failure check, when a task cannot be removed from the outgoing
cpu in the scheduler code, so bringing it back is not really giving any
extra value.
Fixes: 530e9b76ae8f ("cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Link: http://lkml.kernel.org/r/20170608085544.2257132-1-arnd@arndb.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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If we failed to acquire task's cred_guard_mutex we shouldn't proceed
to release it in the error path.
Fixes: a63fbed776c ("perf/tracing/cpuhotplug: Fix locking order")
Signed-off-by: Alexander Levin <alexander.levin@verizon.com>
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: mhiramat@kernel.org
Cc: paulmck@linux.vnet.ibm.com
Cc: bigeasy@linutronix.de
Link: http://lkml.kernel.org/r/20170603033903.12056-1-alexander.levin@verizon.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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The CPU hotplug callbacks are not covered by lockdep versus the cpu hotplug
rwsem.
CPU0 CPU1
cpuhp_setup_state(STATE, startup, teardown);
cpus_read_lock();
invoke_callback_on_ap();
kick_hotplug_thread(ap);
wait_for_completion(); hotplug_thread_fn()
lock(m);
do_stuff();
unlock(m);
Lockdep does not know about this dependency and will not trigger on the
following code sequence:
lock(m);
cpus_read_lock();
Add a lockdep map and connect the initiators lock chain with the hotplug
thread lock chain, so potential deadlocks can be detected.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081549.709375845@linutronix.de
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With the enhanced CPU hotplug lockdep coverage the following lockdep splat
happens:
======================================================
WARNING: possible circular locking dependency detected
4.12.0-rc2+ #84 Tainted: G W
------------------------------------------------------
cpuhp/1/15 is trying to acquire lock:
flush_work+0x39/0x2f0
but task is already holding lock:
cpuhp_thread_fun+0x30/0x160
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (cpuhp_state){+.+.+.}:
lock_acquire+0xb4/0x200
cpuhp_kick_ap_work+0x72/0x330
_cpu_down+0x8b/0x100
do_cpu_down+0x3e/0x60
cpu_down+0x10/0x20
cpu_subsys_offline+0x14/0x20
device_offline+0x88/0xb0
online_store+0x4c/0xa0
dev_attr_store+0x18/0x30
sysfs_kf_write+0x45/0x60
kernfs_fop_write+0x156/0x1e0
__vfs_write+0x37/0x160
vfs_write+0xca/0x1c0
SyS_write+0x58/0xc0
entry_SYSCALL_64_fastpath+0x23/0xc2
-> #1 (cpu_hotplug_lock.rw_sem){++++++}:
lock_acquire+0xb4/0x200
cpus_read_lock+0x3d/0xb0
apply_workqueue_attrs+0x17/0x50
__alloc_workqueue_key+0x1e1/0x530
scsi_host_alloc+0x373/0x480 [scsi_mod]
ata_scsi_add_hosts+0xcb/0x130 [libata]
ata_host_register+0x11a/0x2c0 [libata]
ata_host_activate+0xf0/0x150 [libata]
ahci_host_activate+0x13e/0x170 [libahci]
ahci_init_one+0xa3a/0xd3f [ahci]
local_pci_probe+0x45/0xa0
work_for_cpu_fn+0x14/0x20
process_one_work+0x1f9/0x690
worker_thread+0x200/0x3d0
kthread+0x138/0x170
ret_from_fork+0x31/0x40
-> #0 ((&wfc.work)){+.+.+.}:
__lock_acquire+0x11e1/0x13e0
lock_acquire+0xb4/0x200
flush_work+0x5c/0x2f0
work_on_cpu+0xa1/0xd0
acpi_processor_get_throttling+0x3d/0x50
acpi_processor_reevaluate_tstate+0x2c/0x50
acpi_soft_cpu_online+0x69/0xd0
cpuhp_invoke_callback+0xb4/0x8b0
cpuhp_up_callbacks+0x36/0xc0
cpuhp_thread_fun+0x14e/0x160
smpboot_thread_fn+0x1e8/0x300
kthread+0x138/0x170
ret_from_fork+0x31/0x40
other info that might help us debug this:
Chain exists of:
(&wfc.work) --> cpu_hotplug_lock.rw_sem --> cpuhp_state
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(cpuhp_state);
lock(cpu_hotplug_lock.rw_sem);
lock(cpuhp_state);
lock((&wfc.work));
*** DEADLOCK ***
1 lock held by cpuhp/1/15:
cpuhp_thread_fun+0x30/0x160
stack backtrace:
CPU: 1 PID: 15 Comm: cpuhp/1 Tainted: G W 4.12.0-rc2+ #84
Hardware name: Supermicro SYS-4048B-TR4FT/X10QBi, BIOS 1.1a 07/29/2015
Call Trace:
dump_stack+0x85/0xc4
print_circular_bug+0x209/0x217
__lock_acquire+0x11e1/0x13e0
lock_acquire+0xb4/0x200
? lock_acquire+0xb4/0x200
? flush_work+0x39/0x2f0
? acpi_processor_start+0x50/0x50
flush_work+0x5c/0x2f0
? flush_work+0x39/0x2f0
? acpi_processor_start+0x50/0x50
? mark_held_locks+0x6d/0x90
? queue_work_on+0x56/0x90
? trace_hardirqs_on_caller+0x154/0x1c0
? trace_hardirqs_on+0xd/0x10
? acpi_processor_start+0x50/0x50
work_on_cpu+0xa1/0xd0
? find_worker_executing_work+0x50/0x50
? acpi_processor_power_exit+0x70/0x70
acpi_processor_get_throttling+0x3d/0x50
acpi_processor_reevaluate_tstate+0x2c/0x50
acpi_soft_cpu_online+0x69/0xd0
cpuhp_invoke_callback+0xb4/0x8b0
? lock_acquire+0xb4/0x200
? padata_replace+0x120/0x120
cpuhp_up_callbacks+0x36/0xc0
cpuhp_thread_fun+0x14e/0x160
smpboot_thread_fn+0x1e8/0x300
kthread+0x138/0x170
? sort_range+0x30/0x30
? kthread_create_on_node+0x70/0x70
ret_from_fork+0x31/0x40
The problem is that the work is scheduled on the current CPU from the
hotplug thread associated with that CPU.
It's not required to invoke these functions via the workqueue because the
hotplug thread runs on the target CPU already.
Check whether current is a per cpu thread pinned on the target CPU and
invoke the function directly to avoid the workqueue.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20170524081549.620489733@linutronix.de
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Provide a helper function for checking whether current task is a per cpu
thread.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081549.541649540@linutronix.de
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There are no more (known) nested calls to get_online_cpus() and all
observed lock ordering problems have been addressed.
Replace the magic nested 'rwsem' hackery with a percpu-rwsem.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081549.447014063@linutronix.de
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The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.
Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20170524081549.354513406@linutronix.de
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The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.
Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170524081549.275871311@linutronix.de
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The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.
Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170524081549.197070135@linutronix.de
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Converting the cpu hotplug locking to a percpu rwsem unearthed hidden lock
ordering problems.
There is a wide range of locks involved in this: kprobe_mutex,
jump_label_mutex, ftrace_lock, text_mutex, event_mutex, module_mutex,
func_hash->regex_lock and a gazillion of lock order permutations with
nested get_online_cpus() calls.
Some of those permutations are potential deadlocks even with the current
nesting hotplug locking scheme, but they can't be discovered by lockdep.
The conversion of the hotplug locking to a percpu rwsem requires to prevent
nested locking, so it's required to take the hotplug rwsem early in the
call chain and establish a proper lock order.
After quite some analysis and going down the wrong road severa times the
following lock order has been chosen:
kprobe_mutex -> cpus_rwsem -> jump_label_mutex -> text_mutex
For kprobes which hook on an ftrace function trace point, it's required to
drop cpus_rwsem before calling into the ftrace code to avoid a deadlock on
the func_hash->regex_lock.
[ Steven: Ftrace interaction fixes ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/20170524081549.104864779@linutronix.de
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The conversion of the hotplug locking to a percpu rwsem unearthed lock
ordering issues all over the place.
The jump_label code has two issues:
1) Nested get_online_cpus() invocations
2) Ordering problems vs. the cpus rwsem and the jump_label_mutex
To cure these, the following lock order has been established;
cpus_rwsem -> jump_label_lock -> text_mutex
Even if not all architectures need protection against CPU hotplug, taking
cpus_rwsem before jump_label_lock is now mandatory in code pathes which
actually modify code and therefor need text_mutex protection.
Move the get_online_cpus() invocations into the core jump label code and
establish the proper lock order where required.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: http://lkml.kernel.org/r/20170524081549.025830817@linutronix.de
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perf, tracing, kprobes and jump_labels have a gazillion of ways to create
dependency lock chains. Some of those involve nested invocations of
get_online_cpus().
The conversion of the hotplug locking to a percpu rwsem requires to avoid
such nested calls. sys_perf_event_open() protects most of the syscall logic
against cpu hotplug. This causes nested calls and lock inversions versus
ftrace and kprobes in various interesting ways.
It's impossible to move the hotplug locking to the outer end of all call
chains in the involved facilities, so the hotplug protection in
sys_perf_event_open() needs to be solved differently.
Introduce 'pmus_mutex' which protects a perf private online cpumask. This
mutex is taken when the mask is updated in the cpu hotplug callbacks and
can be taken in sys_perf_event_open() to protect the swhash setup/teardown
code and when the final judgement about a valid event has to be made.
[ tglx: Produced changelog and fixed the swhash interaction ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: http://lkml.kernel.org/r/20170524081548.930941109@linutronix.de
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Converting the hotplug locking, i.e. get_online_cpus(), to a percpu rwsem
unearthed a circular lock dependency which was hidden from lockdep due to
the lockdep annotation of get_online_cpus() which prevents lockdep from
creating full dependency chains.
CPU0 CPU1
---- ----
lock((&wfc.work));
lock(cpu_hotplug_lock.rw_sem);
lock((&wfc.work));
lock(cpu_hotplug_lock.rw_sem);
This dependency is established via acpi_processor_start() which calls into
the work queue code. And the work queue code establishes the reverse
dependency.
This is not a problem of get_online_cpus() recursion, it's a possible
deadlock undetected by lockdep so far.
The cure is to use cpu_hotplug_disable() instead of get_online_cpus() to
protect the probing from acpi_processor_start().
There is a side effect to this: cpu_hotplug_disable() makes a concurrent
cpu hotplug attempt via the sysfs interfaces fail with -EBUSY, but that
probing usually happens during the boot process where no interaction is
possible. Any later invocations are infrequent enough and concurrent
hotplug attempts are so unlikely that the danger of user space visible
regressions is very close to zero. Anyway, thats preferrable over a real
deadlock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20170524081548.851588594@linutronix.de
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pci_call_probe() can called recursively when a physcial function is probed
and the probing creates virtual functions, which are populated via
pci_bus_add_device() which in turn can end up calling pci_call_probe()
again.
The code has an interesting way to prevent recursing into the workqueue
code. That's accomplished by a check whether the current task runs already
on the numa node which is associated with the device.
While that works to prevent the recursion into the workqueue code, it's
racy versus normal execution as there is no guarantee that the node does
not vanish after the check.
There is another issue with this code. It dereferences cpumask_of_node()
unconditionally without checking whether the node is available.
Make the detection reliable by:
- Mark a probed device as 'is_probed' in pci_call_probe()
- Check in pci_call_probe for a virtual function. If it's a virtual
function and the associated physical function device is marked
'is_probed' then this is a recursive call, so the call can be invoked in
the calling context.
- Add a check whether the node is online before dereferencing it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-pci@vger.kernel.org
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081548.771457199@linutronix.de
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Converting the hotplug locking, i.e. get_online_cpus(), to a percpu rwsem
unearthed a circular lock dependency which was hidden from lockdep due to
the lockdep annotation of get_online_cpus() which prevents lockdep from
creating full dependency chains. There are several variants of this. And
example is:
Chain exists of:
cpu_hotplug_lock.rw_sem --> drm_global_mutex --> &item->mutex
CPU0 CPU1
---- ----
lock(&item->mutex);
lock(drm_global_mutex);
lock(&item->mutex);
lock(cpu_hotplug_lock.rw_sem);
because there are dependencies through workqueues. The call chain is:
get_online_cpus
apply_workqueue_attrs
__alloc_workqueue_key
ttm_mem_global_init
ast_ttm_mem_global_init
drm_global_item_ref
ast_mm_init
ast_driver_load
drm_dev_register
drm_get_pci_dev
ast_pci_probe
local_pci_probe
work_for_cpu_fn
process_one_work
worker_thread
This is not a problem of get_online_cpus() recursion, it's a possible
deadlock undetected by lockdep so far.
The cure is to use cpu_hotplug_disable() instead of get_online_cpus() to
protect the PCI probing.
There is a side effect to this: cpu_hotplug_disable() makes a concurrent
cpu hotplug attempt via the sysfs interfaces fail with -EBUSY, but PCI
probing usually happens during the boot process where no interaction is
possible. Any later invocations are infrequent enough and concurrent
hotplug attempts are so unlikely that the danger of user space visible
regressions is very close to zero. Anyway, thats preferrable over a real
deadlock.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-pci@vger.kernel.org
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081548.691198590@linutronix.de
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If intel_snb_check_microcode() is invoked via
microcode_init -> perf_check_microcode -> intel_snb_check_microcode
then get_online_cpus() is invoked nested. This works with the current
implementation of get_online_cpus() but prevents converting it to a percpu
rwsem.
intel_snb_check_microcode() is also invoked from intel_sandybridge_quirk()
unprotected.
Drop get_online_cpus() from intel_snb_check_microcode() and add it to
intel_sandybridge_quirk() so both call sites are protected.
Convert *_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20170524081548.594862191@linutronix.de
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The only caller is the microcode update, which cannot be modular.
Drop the export.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20170524081548.515204988@linutronix.de
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takedown_cpu() is a cpu hotplug function invoking stop_machine(). The cpu
hotplug machinery holds the hotplug lock for write.
stop_machine() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.
Use stop_machine_cpuslocked() to avoid the nested call.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081548.423292433@linutronix.de
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set_subcores_per_core() holds get_online_cpus() while invoking stop_machine().
stop_machine() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.
Use stop_machine_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/20170524081548.331016542@linutronix.de
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stp_work_fn() holds get_online_cpus() while invoking stop_machine().
stop_machine() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.
Use stop_machine_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20170524081548.250203087@linutronix.de
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arch_hw_breakpoint_init() holds get_online_cpus() while registerring the
hotplug callbacks.
cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.
Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170524081548.170940729@linutronix.de
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intel_cqm_init() holds get_online_cpus() while registerring the hotplug
callbacks.
cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.
Use cpuhp_setup_state_cpuslocked() to avoid the nested call. Convert
*_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081548.075604046@linutronix.de
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etm_probe4() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().
cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.
Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170524081547.983493849@linutronix.de
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etm_probe() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().
cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.
Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170524081547.889092478@linutronix.de
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kvmppc_alloc_host_rm_ops() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().
cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.
Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: kvm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: kvm-ppc@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Alexander Graf <agraf@suse.com>
Link: http://lkml.kernel.org/r/20170524081547.809616236@linutronix.de
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cpufreq holds get_online_cpus() while invoking cpuhp_setup_state_nocalls()
to make subsys_interface_register() and the registration of hotplug calls
atomic versus cpu hotplug.
cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.
Use cpuhp_setup/remove_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081547.731628408@linutronix.de
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mtrr_save_state() is invoked from native_cpu_up() which is in the context
of a CPU hotplug operation and therefor calling get_online_cpus() is
pointless.
While this works in the current get_online_cpus() implementation it
prevents from converting the hotplug locking to percpu rwsems.
Remove it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081547.651378834@linutronix.de
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