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author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2015-10-21 15:27:36 -0400 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2015-10-25 21:33:56 -0400 |
commit | 8ca532ad2b050da0d0db3544d9ab8b40675e4ca1 (patch) | |
tree | ccba6d4d2730df8ebc3d2ca5747d0006cd2ff762 | |
parent | 3fdaf80f4a836911c0eda1cee92f8aa625f90197 (diff) | |
download | linux-stable-8ca532ad2b050da0d0db3544d9ab8b40675e4ca1.tar.gz linux-stable-8ca532ad2b050da0d0db3544d9ab8b40675e4ca1.tar.bz2 linux-stable-8ca532ad2b050da0d0db3544d9ab8b40675e4ca1.zip |
tracing: Check all tasks on each CPU when filtering pids
My tests found that if a task is running but not filtered when set_event_pid
is modified, then it can still be traced.
Call on_each_cpu() to check if the current running task should be filtered
and update the per cpu flags of tr->data appropriately.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r-- | kernel/trace/trace_events.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index ab07058e27c1..2b7fccd499c6 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1549,6 +1549,22 @@ static int max_pids(struct trace_pid_list *pid_list) return (PAGE_SIZE << pid_list->order) / sizeof(pid_t); } +static void ignore_task_cpu(void *data) +{ + struct trace_array *tr = data; + struct trace_pid_list *pid_list; + + /* + * This function is called by on_each_cpu() while the + * event_mutex is held. + */ + pid_list = rcu_dereference_protected(tr->filtered_pids, + mutex_is_locked(&event_mutex)); + + this_cpu_write(tr->trace_buffer.data->ignore_pid, + check_ignore_pid(pid_list, current)); +} + static ssize_t ftrace_event_pid_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) @@ -1711,6 +1727,12 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf, tr, INT_MAX); register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr, 0); + + /* + * Ignoring of pids is done at task switch. But we have to + * check for those tasks that are currently running. + */ + on_each_cpu(ignore_task_cpu, tr, 1); } mutex_unlock(&event_mutex); |