From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 7 Aug 2024 11:29:27 +0000 (+0200)
Subject: perf: Fix event_function_call() locking
X-Git-Tag: v6.12-rc1~145^2~19
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=558abc7e3f89;p=thirdparty%2Fkernel%2Flinux.git

perf: Fix event_function_call() locking

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
---

diff --git a/kernel/events/core.c b/kernel/events/core.c
index eb03c9ab16700..ab49deae6e6f3 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -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);
 }
 
 /*