[v4] x86: Add a testcase for BZ #29863
Checks
| Context |
Check |
Description |
| dj/TryBot-apply_patch |
success
|
Patch applied to master at the time it was sent
|
| dj/TryBot-32bit |
success
|
Build for i686
|
Commit Message
When a thread is updating the memory area of memcmp and another thread
is doing memcmp, the memcmp return value is undefined. Add a testcase
to verify that memcmp won't segfault in this case.
---
sysdeps/x86/Makefile | 8 +++
sysdeps/x86/tst-memcmp-race.c | 106 ++++++++++++++++++++++++++++++++++
2 files changed, 114 insertions(+)
create mode 100644 sysdeps/x86/tst-memcmp-race.c
@@ -257,3 +257,11 @@ tests += \
tests-static += \
tst-sysconf-cache-linesize-static
endif
+
+ifeq ($(subdir),nptl)
+tests += \
+ tst-memcmp-race \
+# tests
+
+CFLAGS-tst-memcmp-race.c += -O0
+endif
new file mode 100644
@@ -0,0 +1,106 @@
+/* Test case for memcmp with race condition.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+/* Verify that there is no segfault when one thread is updating the
+ memory block of memcmp and the other thread is doing memcmp. */
+
+#define TEST_MAIN
+#define TEST_NAME "memcmp"
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <string/test-string.h>
+#include <support/xthread.h>
+
+#define NUM_THREADS 2
+#define LOOP1 100
+#define LOOP2 1000000
+
+typedef int (*proto_t) (const void *, const void *, size_t);
+
+IMPL (memcmp, 1)
+
+struct arg
+{
+ proto_t func;
+ size_t len;
+ int i;
+};
+
+static void *
+childThread (void *tArgs)
+{
+ struct arg *a = (struct arg *) tArgs;
+ int i;
+
+ if (0 == a->i % 2)
+ {
+ for (i = 0; i < LOOP1; i++)
+ {
+ int result = a->func (buf1, buf2, a->len);
+ printf ("i = %d : result = %d\n", i, result);
+ }
+ }
+ else
+ {
+ size_t offset = a->len > 16 ? a->len - 16 : 1;
+ for (i = 0; i < LOOP2; i++)
+ buf1[offset] = i & 1;
+ }
+
+ return NULL;
+}
+
+static void
+do_one_test (proto_t func, size_t len)
+{
+ int i;
+ pthread_t threads[NUM_THREADS];
+ struct arg a[NUM_THREADS];
+
+ for (i = 0; i < NUM_THREADS; ++i)
+ {
+ a[i].func = func;
+ a[i].len = len;
+ a[i].i = i;
+ threads[i] = xpthread_create (NULL, childThread, (void *)&a[i]);
+ }
+
+ for (i = 0; i < NUM_THREADS; ++i)
+ xpthread_join (threads[i]);
+}
+
+int
+test_main (void)
+{
+ test_init ();
+
+ memset (buf1, 1, page_size);
+ memset (buf2, 1, page_size);
+
+ for (size_t i = 0; i <= 11; i++)
+ {
+ FOR_EACH_IMPL (impl, 0)
+ do_one_test ((proto_t) impl->fn, (1 << i) + 1);
+ }
+
+ return 0;
+}
+
+#include <support/test-driver.c>