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| author | Peter Zijlstra <peterz@infradead.org> | 2014-05-21 17:32:19 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-06-06 07:54:02 +0200 |
| commit | e041e328c4b41e1db79bfe5ba9992c2ed771ad19 (patch) | |
| tree | 88f8689160ae586c728e6ef665cc4c580c116ba9 | |
| parent | 22c91aa23547a4363fd2a9ffddde95c899ac8aa0 (diff) | |
| download | linux-e041e328c4b41e1db79bfe5ba9992c2ed771ad19.tar.gz linux-e041e328c4b41e1db79bfe5ba9992c2ed771ad19.tar.bz2 linux-e041e328c4b41e1db79bfe5ba9992c2ed771ad19.zip | |
perf: Fix perf_event_comm() vs. exec() assumption
perf_event_comm() assumes that set_task_comm() is only called on
exec(), and in particular that its only called on current.
Neither are true, as Dave reported a WARN triggered by set_task_comm()
being called on !current.
Separate the exec() hook from the comm hook.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20140521153219.GH5226@laptop.programming.kicks-ass.net
[ Build fix. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | fs/exec.c | 1 | ||||
| -rw-r--r-- | include/linux/perf_event.h | 4 | ||||
| -rw-r--r-- | kernel/events/core.c | 28 |
3 files changed, 20 insertions, 13 deletions
diff --git a/fs/exec.c b/fs/exec.c index 238b7aa26f68..a038a41a3677 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1110,6 +1110,7 @@ void setup_new_exec(struct linux_binprm * bprm) else set_dumpable(current->mm, suid_dumpable); + perf_event_exec(); set_task_comm(current, kbasename(bprm->filename)); /* Set the new mm task size. We have to do that late because it may diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 3ef6ea12806a..9b5cd1992a88 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -695,6 +695,7 @@ extern struct perf_guest_info_callbacks *perf_guest_cbs; extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks); +extern void perf_event_exec(void); extern void perf_event_comm(struct task_struct *tsk); extern void perf_event_fork(struct task_struct *tsk); @@ -772,7 +773,7 @@ extern void perf_event_enable(struct perf_event *event); extern void perf_event_disable(struct perf_event *event); extern int __perf_event_disable(void *info); extern void perf_event_task_tick(void); -#else +#else /* !CONFIG_PERF_EVENTS: */ static inline void perf_event_task_sched_in(struct task_struct *prev, struct task_struct *task) { } @@ -802,6 +803,7 @@ static inline int perf_unregister_guest_info_callbacks (struct perf_guest_info_callbacks *callbacks) { return 0; } static inline void perf_event_mmap(struct vm_area_struct *vma) { } +static inline void perf_event_exec(void) { } static inline void perf_event_comm(struct task_struct *tsk) { } static inline void perf_event_fork(struct task_struct *tsk) { } static inline void perf_event_init(void) { } diff --git a/kernel/events/core.c b/kernel/events/core.c index 440eefc67397..647698f91988 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2970,6 +2970,22 @@ out: local_irq_restore(flags); } +void perf_event_exec(void) +{ + struct perf_event_context *ctx; + int ctxn; + + rcu_read_lock(); + for_each_task_context_nr(ctxn) { + ctx = current->perf_event_ctxp[ctxn]; + if (!ctx) + continue; + + perf_event_enable_on_exec(ctx); + } + rcu_read_unlock(); +} + /* * Cross CPU call to read the hardware event */ @@ -5057,18 +5073,6 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event) void perf_event_comm(struct task_struct *task) { struct perf_comm_event comm_event; - struct perf_event_context *ctx; - int ctxn; - - rcu_read_lock(); - for_each_task_context_nr(ctxn) { - ctx = task->perf_event_ctxp[ctxn]; - if (!ctx) - continue; - - perf_event_enable_on_exec(ctx); - } - rcu_read_unlock(); if (!atomic_read(&nr_comm_events)) return; |