Module Name: src
Committed By: ozaki-r
Date: Thu Dec 28 04:38:02 UTC 2017
Modified Files:
src/tests/rump/kernspace: workqueue.c
Log Message:
Fix a race condition on taking the mutex
The workqueue worker can take the mutex before the tester tries to take it after
calling workqueue_enqueue. If it happens, the worker calls cv_broadcast before
the tester calls cv_timedwait and the tester will wait until the cv timed out
Take the mutex before calling workqueue_enqueue so that the tester surely calls
cv_timedwait before the worker calls cv_broadcast.
The fix stabilizes the test, t_workqueue/workqueue1.
To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/tests/rump/kernspace/workqueue.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/tests/rump/kernspace/workqueue.c
diff -u src/tests/rump/kernspace/workqueue.c:1.2 src/tests/rump/kernspace/workqueue.c:1.3
--- src/tests/rump/kernspace/workqueue.c:1.2 Thu Dec 28 04:36:15 2017
+++ src/tests/rump/kernspace/workqueue.c Thu Dec 28 04:38:02 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: workqueue.c,v 1.2 2017/12/28 04:36:15 ozaki-r Exp $ */
+/* $NetBSD: workqueue.c,v 1.3 2017/12/28 04:38:02 ozaki-r Exp $ */
/*-
* Copyright (c) 2017 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
#include <sys/cdefs.h>
#if !defined(lint)
-__RCSID("$NetBSD: workqueue.c,v 1.2 2017/12/28 04:36:15 ozaki-r Exp $");
+__RCSID("$NetBSD: workqueue.c,v 1.3 2017/12/28 04:38:02 ozaki-r Exp $");
#endif /* !lint */
#include <sys/param.h>
@@ -84,8 +84,8 @@ rumptest_workqueue1()
#define ITERATIONS 12435
for (size_t i = 0; i < ITERATIONS; ++i) {
int e;
- workqueue_enqueue(sc->wq, &sc->wk, NULL);
mutex_enter(&sc->mtx);
+ workqueue_enqueue(sc->wq, &sc->wk, NULL);
e = cv_timedwait(&sc->cv, &sc->mtx, hz * 2);
if (e != 0)
panic("cv_timedwait timed out (i=%lu)", i);
