This is a note to let you know that I've just added the patch titled
perf: Really fix event_function_call() locking
to the 6.11-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-really-fix-event_function_call-locking.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit bb84165569571e191298163231994672056fb8e3
Author: Namhyung Kim <namhyung@xxxxxxxxxx>
Date: Tue Aug 13 22:55:11 2024 +0200
perf: Really fix event_function_call() locking
[ Upstream commit fe826cc2654e8561b64246325e6a51b62bf2488c ]
Commit 558abc7e3f89 ("perf: Fix event_function_call() locking") lost
IRQ disabling by mistake.
Fixes: 558abc7e3f89 ("perf: Fix event_function_call() locking")
Reported-by: Pengfei Xu <pengfei.xu@xxxxxxxxx>
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Tested-by: Pengfei Xu <pengfei.xu@xxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4339df585d42d..62a5d50b850ed 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -263,8 +263,8 @@ 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 perf_cpu_context *cpuctx;
struct event_function_struct efs = {
.event = event,
.func = func,
@@ -292,22 +292,25 @@ static void event_function_call(struct perf_event *event, event_f func, void *da
if (!task_function_call(task, event_function, &efs))
return;
+ local_irq_disable();
+ cpuctx = this_cpu_ptr(&perf_cpu_context);
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) {
- perf_ctx_unlock(cpuctx, ctx);
- return;
- }
+ if (task == TASK_TOMBSTONE)
+ goto unlock;
if (ctx->is_active) {
perf_ctx_unlock(cpuctx, ctx);
+ local_irq_enable();
goto again;
}
func(event, NULL, ctx, data);
+unlock:
perf_ctx_unlock(cpuctx, ctx);
+ local_irq_enable();
}
/*
