Merge tag 'perf-urgent-2020-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

aa5c3a29 · Linus Torvalds <[email protected]> · 2020-10-11 10:43:37 -07:00

Pull perf fix from Ingo Molnar:
 "Fix an error handling bug that can cause a lockup if a CPU is offline
  (doh ...)"

* tag 'perf-urgent-2020-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix task_function_call() error handling

Commit: aa5c3a2911e6d5feaf0c3c7af5bbc652f129d8b2
Parents: da690031 · 6d6b8b9f

Merge commit. Changes below are compared with the first parent: da690031.

Changes

1 files changed · +3 −2

File	Status	Add	Del	Content
kernel/events/core.c	modified	+3	−2	View file

kernel/events/core.c

View file

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 7ed5248..e8bf922 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -99,7 +99,7 @@ static void remote_function(void *data)
  * retry due to any failures in smp_call_function_single(), such as if the
  * task_cpu() goes offline concurrently.
  *
- * returns @func return value or -ESRCH when the process isn't running
+ * returns @func return value or -ESRCH or -ENXIO when the process isn't running
  */
 static int
 task_function_call(struct task_struct *p, remote_function_f func, void *info)
@@ -115,7 +115,8 @@ task_function_call(struct task_struct *p, remote_function_f func, void *info)
 	for (;;) {
 		ret = smp_call_function_single(task_cpu(p), remote_function,
 					       &data, 1);
-		ret = !ret ? data.ret : -EAGAIN;
+		if (!ret)
+			ret = data.ret;
 
 		if (ret != -EAGAIN)
 			break;