@@ -80,7 +80,8 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \
tst-strtol-locale tst-strtod-nan-locale tst-strfmon_l \
tst-quick_exit tst-thread-quick_exit tst-width \
tst-width-stdint tst-strfrom tst-strfrom-locale \
- tst-getrandom
+ tst-getrandom test-atexit-race test-at_quick_exit-race \
+ test-__cxa_atexit-race
tests-internal := tst-strtod1i tst-strtod3 tst-strtod4 tst-strtod5i \
tst-tls-atexit tst-tls-atexit-nodelete
tests-static := tst-secure-getenv
@@ -89,6 +90,10 @@ ifeq ($(build-hardcoded-path-in-tests),yes)
tests += tst-empty-env
endif
+LDLIBS-test-atexit-race = $(shared-thread-library)
+LDLIBS-test-at_quick_exit-race = $(shared-thread-library)
+LDLIBS-test-__cxa_atexit-race = $(shared-thread-library)
+
ifeq ($(have-cxx-thread_local),yes)
CFLAGS-tst-quick_exit.o = -std=c++11
LDLIBS-tst-quick_exit = -lstdc++
@@ -26,16 +26,25 @@
#undef __cxa_atexit
+/* We change global data, so we need locking. */
+__libc_lock_define_initialized (, __exit_funcs_lock)
+
int
attribute_hidden
__internal_atexit (void (*func) (void *), void *arg, void *d,
struct exit_function_list **listp)
{
- struct exit_function *new = __new_exitfn (listp);
+ struct exit_function *new;
+
+ __libc_lock_lock (__exit_funcs_lock);
+ new = __new_exitfn (listp);
if (new == NULL)
- return -1;
+ {
+ __libc_lock_unlock (__exit_funcs_lock);
+ return -1;
+ }
#ifdef PTR_MANGLE
PTR_MANGLE (func);
@@ -45,6 +54,7 @@ __internal_atexit (void (*func) (void *), void *arg, void *d,
new->func.cxa.dso_handle = d;
atomic_write_barrier ();
new->flavor = ef_cxa;
+ __libc_lock_unlock (__exit_funcs_lock);
return 0;
}
@@ -60,10 +70,6 @@ __cxa_atexit (void (*func) (void *), void *arg, void *d)
libc_hidden_def (__cxa_atexit)
-/* We change global data, so we need locking. */
-__libc_lock_define_initialized (static, lock)
-
-
static struct exit_function_list initial;
struct exit_function_list *__exit_funcs = &initial;
uint64_t __new_exitfn_called;
@@ -76,7 +82,10 @@ __new_exitfn (struct exit_function_list **listp)
struct exit_function *r = NULL;
size_t i = 0;
- __libc_lock_lock (lock);
+ if (__exit_funcs_done == 1)
+ /* exit code finished processing all handlers
+ so fail this registration */
+ return NULL;
for (l = *listp; l != NULL; p = l, l = l->next)
{
@@ -127,7 +136,5 @@ __new_exitfn (struct exit_function_list **listp)
++__new_exitfn_called;
}
- __libc_lock_unlock (lock);
-
return r;
}
@@ -19,11 +19,14 @@
#include <stdlib.h>
#include <unistd.h>
#include <sysdep.h>
+#include <libc-lock.h>
#include "exit.h"
#include "set-hooks.h"
DEFINE_HOOK (__libc_atexit, (void))
+/* initialise the processing complete flag to 0 */
+int __exit_funcs_done = 0;
/* Call all functions registered with `atexit' and `on_exit',
in the reverse of the order in which they were registered
@@ -44,14 +47,30 @@ __run_exit_handlers (int status, struct exit_function_list **listp,
the functions registered with `atexit' and `on_exit'. We call
everyone on the list and use the status value in the last
exit (). */
- while (*listp != NULL)
+ while (true)
{
- struct exit_function_list *cur = *listp;
+ struct exit_function_list *cur;
+
+ restart:
+ __libc_lock_lock (__exit_funcs_lock);
+ cur = *listp;
+
+ if (cur == NULL)
+ {
+ /* Exit processing complete. We will not allow any more
+ atexit/on_exit registrations. */
+ __exit_funcs_done = 1;
+ __libc_lock_unlock (__exit_funcs_lock);
+ break;
+ }
while (cur->idx > 0)
{
const struct exit_function *const f =
&cur->fns[--cur->idx];
+ const uint64_t new_exitfn_called = __new_exitfn_called;
+
+ __libc_lock_unlock (__exit_funcs_lock);
switch (f->flavor)
{
void (*atfct) (void);
@@ -83,6 +102,15 @@ __run_exit_handlers (int status, struct exit_function_list **listp,
cxafct (f->func.cxa.arg, status);
break;
}
+ __libc_lock_lock (__exit_funcs_lock);
+
+ if (__glibc_unlikely (new_exitfn_called != __new_exitfn_called))
+ {
+ /* The last exit function, or another thread, has registered
+ more exit functions. Start the loop over. */
+ __libc_lock_unlock (__exit_funcs_lock);
+ goto restart;
+ }
}
*listp = cur->next;
@@ -90,6 +118,8 @@ __run_exit_handlers (int status, struct exit_function_list **listp,
/* Don't free the last element in the chain, this is the statically
allocate element. */
free (cur);
+
+ __libc_lock_unlock (__exit_funcs_lock);
}
if (run_list_atexit)
@@ -20,6 +20,7 @@
#include <stdbool.h>
#include <stdint.h>
+#include <libc-lock.h>
enum
{
@@ -62,6 +63,10 @@ extern struct exit_function_list *__quick_exit_funcs attribute_hidden;
extern struct exit_function *__new_exitfn (struct exit_function_list **listp);
extern uint64_t __new_exitfn_called attribute_hidden;
+__libc_lock_define (extern, __exit_funcs_lock);
+
+/* flag to mark that all registered atexit/onexit handlers are called */
+extern int __exit_funcs_done attribute_hidden;
extern void __run_exit_handlers (int status,
struct exit_function_list **listp,
@@ -24,10 +24,16 @@
int
__on_exit (void (*func) (int status, void *arg), void *arg)
{
- struct exit_function *new = __new_exitfn (&__exit_funcs);
+ struct exit_function *new;
+
+ __libc_lock_lock (__exit_funcs_lock);
+ new = __new_exitfn (&__exit_funcs);
if (new == NULL)
- return -1;
+ {
+ __libc_lock_unlock (__exit_funcs_lock);
+ return -1;
+ }
#ifdef PTR_MANGLE
PTR_MANGLE (func);
@@ -36,6 +42,7 @@ __on_exit (void (*func) (int status, void *arg), void *arg)
new->func.on.arg = arg;
atomic_write_barrier ();
new->flavor = ef_on;
+ __libc_lock_unlock (__exit_funcs_lock);
return 0;
}
weak_alias (__on_exit, on_exit)
new file mode 100644
@@ -0,0 +1,34 @@
+/* A test for __cxa_atexit/exit race from bz14333.
+
+ Copyright (C) 2017 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
+ <http://www.gnu.org/licenses/>. */
+
+/* This file must be run from within a directory called "stdlib". */
+
+#include <stdio.h>
+
+#define CALL_ATEXIT __cxa_atexit (&no_op, NULL, NULL)
+#define CALL_EXIT exit (0)
+
+int __cxa_atexit (void (*func) (void *), void *arg, void *d);
+
+static void
+no_op (void *ignored)
+{
+}
+
+#include <stdlib/test-atexit-race-common.c>
new file mode 100644
@@ -0,0 +1,30 @@
+/* A test for at_quick_exit/quick_exit race from bz14333.
+
+ Copyright (C) 2017 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
+ <http://www.gnu.org/licenses/>. */
+
+/* This file must be run from within a directory called "stdlib". */
+
+#define CALL_ATEXIT at_quick_exit (&no_op)
+#define CALL_EXIT quick_exit (0)
+
+static void
+no_op (void)
+{
+}
+
+#include <stdlib/test-atexit-race-common.c>
new file mode 100644
@@ -0,0 +1,62 @@
+/* Support file for atexit/exit, at_quick_exit/quick_exit, etc. race tests
+ from bz14333.
+
+ Copyright (C) 2017 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
+ <http://www.gnu.org/licenses/>. */
+
+/* This file must be run from within a directory called "stdlib". */
+
+#if !defined(CALL_EXIT) || !defined(CALL_ATEXIT)
+#error Must define CALL_EXIT and CALL_ATEXIT before using this file.
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+
+const size_t kNumThreads = 1024;
+const size_t kNumHandlers = 1024;
+
+static void *
+threadfunc (void *unused)
+{
+ size_t i;
+ for (i = 0; i < kNumHandlers; ++i) {
+ CALL_ATEXIT;
+ }
+ return NULL;
+}
+
+static int
+do_test (void)
+{
+ size_t i;
+ pthread_t thr;
+ pthread_attr_t attr;
+
+ pthread_attr_init (&attr);
+ pthread_attr_setdetachstate (&attr, 1);
+
+ for (i = 0; i < kNumThreads; ++i) {
+ pthread_create (&thr, &attr, threadfunc, NULL);
+ }
+
+ CALL_EXIT;
+}
+
+#define TEST_FUNCTION do_test
+#include <support/test-driver.c>
new file mode 100644
@@ -0,0 +1,30 @@
+/* A test for atexit/exit race from bz14333.
+
+ Copyright (C) 2017 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
+ <http://www.gnu.org/licenses/>. */
+
+/* This file must be run from within a directory called "stdlib". */
+
+#define CALL_ATEXIT atexit (&no_op)
+#define CALL_EXIT exit (0)
+
+static void
+no_op (void)
+{
+}
+
+#include <stdlib/test-atexit-race-common.c>