Module Name: src
Committed By: riastradh
Date: Sun Mar 30 23:03:06 UTC 2025
Modified Files:
src/tests/lib/libpthread: t_once.c
Log Message:
tests/lib/libpthread/t_once: Test fork and pthread_once race.
Test is disabled by default because it triggers only with very low
probability in each trial, but let's make it easy to run if you want.
PR lib/59125: pthread_once(3) races with concurrent fork
To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/tests/lib/libpthread/t_once.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/lib/libpthread/t_once.c
diff -u src/tests/lib/libpthread/t_once.c:1.2 src/tests/lib/libpthread/t_once.c:1.3
--- src/tests/lib/libpthread/t_once.c:1.2 Fri Aug 25 22:59:47 2017
+++ src/tests/lib/libpthread/t_once.c Sun Mar 30 23:03:06 2025
@@ -1,4 +1,4 @@
-/* $NetBSD: t_once.c,v 1.2 2017/08/25 22:59:47 ginsbach Exp $ */
+/* $NetBSD: t_once.c,v 1.3 2025/03/30 23:03:06 riastradh Exp $ */
/*
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -29,17 +29,21 @@
#include <sys/cdefs.h>
__COPYRIGHT("@(#) Copyright (c) 2008\
The NetBSD Foundation, inc. All rights reserved.");
-__RCSID("$NetBSD: t_once.c,v 1.2 2017/08/25 22:59:47 ginsbach Exp $");
+__RCSID("$NetBSD: t_once.c,v 1.3 2025/03/30 23:03:06 riastradh Exp $");
#include <sys/time.h>
+#include <sys/wait.h>
+
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
+#include <unistd.h>
#include <atf-c.h>
#include "h_common.h"
+#include "h_macros.h"
static pthread_once_t once = PTHREAD_ONCE_INIT;
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
@@ -54,6 +58,12 @@ ofunc(void)
x++;
}
+static void
+ofunc_silent(void)
+{
+ x++;
+}
+
ATF_TC(once1);
ATF_TC_HEAD(once1, tc)
{
@@ -187,11 +197,75 @@ ATF_TC_BODY(once3, tc)
printf("Test succeeded\n");
}
+static long trial;
+
+static void *
+fork_and_once(void *cookie)
+{
+ pthread_barrier_t *bar = cookie;
+ pid_t pid, child;
+ int status;
+
+ (void)pthread_barrier_wait(bar);
+ RL(pid = fork());
+ if (pid == 0) {
+ (void)alarm(1);
+ (void)pthread_once(&once, &ofunc_silent);
+ _exit(x - 1);
+ }
+ RL(child = waitpid(pid, &status, 0));
+ ATF_REQUIRE_EQ_MSG(child, pid, "child=%lld pid=%lld",
+ (long long)child, (long long)pid);
+ ATF_REQUIRE_MSG(!WIFSIGNALED(status),
+ "child exited on signal %d (%s) in trial %ld",
+ WTERMSIG(status), strsignal(WTERMSIG(status)), trial);
+ ATF_REQUIRE_MSG(WIFEXITED(status) && WEXITSTATUS(status) == 0,
+ "child exited 0x%x in trial %ld", status, trial);
+ return NULL;
+}
+
+ATF_TC(oncefork);
+ATF_TC_HEAD(oncefork, tc)
+{
+ atf_tc_set_md_var(tc, "descr", "Test racing pthread_once with fork");
+}
+ATF_TC_BODY(oncefork, tc)
+{
+ static pthread_once_t once0 = PTHREAD_ONCE_INIT;
+ pthread_barrier_t bar;
+ long ntrials = atf_tc_get_config_var_as_long_wd(tc,
+ "pthread_once_forktrials", 0);
+
+ if (ntrials <= 0) {
+ atf_tc_skip("pthread_once takes thousands of fork trials"
+ " on a multicore system to detect a race; set"
+ " pthread_once_forktrials to the number of trials to"
+ " enable this test");
+ }
+
+ RZ(pthread_barrier_init(&bar, NULL, 2));
+
+ for (trial = 0; trial < ntrials; trial++) {
+ pthread_t t;
+
+ once = once0;
+ x = 0;
+
+ RZ(pthread_create(&t, NULL, &fork_and_once, &bar));
+ (void)alarm(1);
+ (void)pthread_barrier_wait(&bar);
+ (void)pthread_once(&once, &ofunc_silent);
+ (void)alarm(0);
+ RZ(pthread_join(t, NULL));
+ }
+}
+
ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, once1);
ATF_TP_ADD_TC(tp, once2);
ATF_TP_ADD_TC(tp, once3);
+ ATF_TP_ADD_TC(tp, oncefork);
return atf_no_error();
}
