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perf: Fix event_function_call() locking

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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@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240807115550.138301094@infradead.org
This commit is contained in:
Peter Zijlstra 2024-08-07 13:29:27 +02:00
parent 9a32bd9901
commit 558abc7e3f
1 changed files with 5 additions and 4 deletions
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9
kernel/events/core.c
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@ -263,6 +263,7 @@ unlock:
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 @@ again:
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);
}
/*