From: Davidlohr Bueso <dave@stgolabs.net>
Date: Mon, 9 Aug 2021 04:33:00 +0000 (-0700)
Subject: perf bench futex, requeue: Robustify futex_wait() handling
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6f9661b25b1741b180bdaeb85853905078cfd9d8;p=linux.git

perf bench futex, requeue: Robustify futex_wait() handling

Do not assume success and account for EAGAIN or any other return value,
however unlikely.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lore.kernel.org/lkml/20210809043301.66002-7-dave@stgolabs.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c
index 6606569e7ccc3..e23a08037de28 100644
--- a/tools/perf/bench/futex-requeue.c
+++ b/tools/perf/bench/futex-requeue.c
@@ -77,6 +77,8 @@ static void print_summary(void)
 
 static void *workerfn(void *arg __maybe_unused)
 {
+	int ret;
+
 	pthread_mutex_lock(&thread_lock);
 	threads_starting--;
 	if (!threads_starting)
@@ -84,7 +86,18 @@ static void *workerfn(void *arg __maybe_unused)
 	pthread_cond_wait(&thread_worker, &thread_lock);
 	pthread_mutex_unlock(&thread_lock);
 
-	futex_wait(&futex1, 0, NULL, futex_flag);
+	while (1) {
+		ret = futex_wait(&futex1, 0, NULL, futex_flag);
+		if (!ret)
+			break;
+
+		if (ret && errno != EAGAIN) {
+			if (!params.silent)
+				warn("futex_wait");
+			break;
+		}
+	}
+
 	return NULL;
 }