This is a note to let you know that I've just added the patch titled
perf: Fix event_function_call() locking
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-fix-event_function_call-locking.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 74f9c2fd720239198a0e07132f854a6f4e1216c8
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Wed Aug 7 13:29:27 2024 +0200
perf: Fix event_function_call() locking
[ Upstream commit 558abc7e3f895049faa46b08656be4c60dc6e9fd ]
All the event_function/@func call context already uses perf_ctx_lock()
except for the !ctx->is_active case. Make it all consistent.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Reviewed-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240807115550.138301094@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d40809bdf4b30..18eab7f50ecce 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -263,6 +263,7 @@ static int event_function(void *info)
static void event_function_call(struct perf_event *event, event_f func, void *data)
{
struct perf_event_context *ctx = event->ctx;
+ struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
struct event_function_struct efs = {
.event = event,
@@ -291,22 +292,22 @@ static void event_function_call(struct perf_event *event, event_f func, void *da
if (!task_function_call(task, event_function, &efs))
return;
- raw_spin_lock_irq(&ctx->lock);
+ perf_ctx_lock(cpuctx, ctx);
/*
* Reload the task pointer, it might have been changed by
* a concurrent perf_event_context_sched_out().
*/
task = ctx->task;
if (task == TASK_TOMBSTONE) {
- raw_spin_unlock_irq(&ctx->lock);
+ perf_ctx_unlock(cpuctx, ctx);
return;
}
if (ctx->is_active) {
- raw_spin_unlock_irq(&ctx->lock);
+ perf_ctx_unlock(cpuctx, ctx);
goto again;
}
func(event, NULL, ctx, data);
- raw_spin_unlock_irq(&ctx->lock);
+ perf_ctx_unlock(cpuctx, ctx);
}
/*
