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[binutils-gdb] testsuite: Fix race condition in check-libthread-db
- From: Alan Hayward <alahay01 at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 27 Sep 2018 09:49:38 -0000
- Subject: [binutils-gdb] testsuite: Fix race condition in check-libthread-db
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=9fc3183f0f8ab8ec85f0e5f65bae9e18ddf545a0
commit 9fc3183f0f8ab8ec85f0e5f65bae9e18ddf545a0
Author: Alan Hayward <alan.hayward@arm.com>
Date: Wed Sep 26 14:06:54 2018 +0100
testsuite: Fix race condition in check-libthread-db
It is possible for the created thread to reach the breakpoint before
the main thread has set errno to 23.
Prevent this using a pthread barrier.
* gdb.threads/check-libthread-db.c (thread_routine): Use a
pthread barrier.
(main): Likewise.
Diff:
---
gdb/testsuite/ChangeLog | 6 ++++++
gdb/testsuite/gdb.threads/check-libthread-db.c | 8 ++++++++
2 files changed, 14 insertions(+)
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 2b4b097..2072705 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2018-09-27 Alan Hayward <alan.hayward@arm.com>
+
+ * gdb.threads/check-libthread-db.c (thread_routine): Use a
+ pthread barrier.
+ (main): Likewise.
+
2018-09-26 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.base/large-frame-1.c: New file.
diff --git a/gdb/testsuite/gdb.threads/check-libthread-db.c b/gdb/testsuite/gdb.threads/check-libthread-db.c
index 85a97a9..2d9aec4 100644
--- a/gdb/testsuite/gdb.threads/check-libthread-db.c
+++ b/gdb/testsuite/gdb.threads/check-libthread-db.c
@@ -23,6 +23,10 @@
#include <pthread.h>
#include <errno.h>
+/* This barrier ensures we only reach the initial breakpoint after both threads
+ have set errno. */
+pthread_barrier_t start_threads_barrier;
+
static void
break_here (void)
{
@@ -32,6 +36,7 @@ static void *
thread_routine (void *arg)
{
errno = 42;
+ pthread_barrier_wait (&start_threads_barrier);
break_here ();
@@ -47,6 +52,8 @@ main (int argc, char *argv)
pthread_t the_thread;
int err;
+ pthread_barrier_init (&start_threads_barrier, NULL, 2);
+
err = pthread_create (&the_thread, NULL, thread_routine, NULL);
if (err != 0)
{
@@ -55,6 +62,7 @@ main (int argc, char *argv)
}
errno = 23;
+ pthread_barrier_wait (&start_threads_barrier);
err = pthread_join (the_thread, NULL);
if (err != 0)