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-rw-r--r--stdlib/Makefile10
-rw-r--r--stdlib/exit.c6
-rw-r--r--stdlib/test-dlclose-exit-race-helper.c79
-rw-r--r--stdlib/test-dlclose-exit-race.c80
4 files changed, 171 insertions, 4 deletions
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 2fb0834..0a51b7b 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -83,7 +83,7 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \
tst-getrandom tst-atexit tst-at_quick_exit \
tst-cxa_atexit tst-on_exit test-atexit-race \
test-at_quick_exit-race test-cxa_atexit-race \
- test-on_exit-race
+ test-on_exit-race test-dlclose-exit-race
tests-internal := tst-strtod1i tst-strtod3 tst-strtod4 tst-strtod5i \
tst-tls-atexit tst-tls-atexit-nodelete
@@ -98,6 +98,10 @@ LDLIBS-test-at_quick_exit-race = $(shared-thread-library)
LDLIBS-test-cxa_atexit-race = $(shared-thread-library)
LDLIBS-test-on_exit-race = $(shared-thread-library)
+LDLIBS-test-dlclose-exit-race = $(shared-thread-library) $(libdl)
+LDFLAGS-test-dlclose-exit-race = $(LDFLAGS-rdynamic)
+LDLIBS-test-dlclose-exit-race-helper.so = $(libsupport) $(shared-thread-library)
+
ifeq ($(have-cxx-thread_local),yes)
CFLAGS-tst-quick_exit.o = -std=c++11
LDLIBS-tst-quick_exit = -lstdc++
@@ -108,7 +112,7 @@ else
tests-unsupported += tst-quick_exit tst-thread-quick_exit
endif
-modules-names = tst-tls-atexit-lib
+modules-names = tst-tls-atexit-lib test-dlclose-exit-race-helper
extra-test-objs += $(addsuffix .os, $(modules-names))
ifeq ($(build-shared),yes)
@@ -177,6 +181,7 @@ $(objpfx)tst-strtod-nan-locale.out: $(gen-locales)
$(objpfx)tst-strfmon_l.out: $(gen-locales)
$(objpfx)tst-strfrom.out: $(gen-locales)
$(objpfx)tst-strfrom-locale.out: $(gen-locales)
+$(objpfx)test-dlclose-exit-race.out: $(objpfx)test-dlclose-exit-race-helper.so
endif
# Testdir has to be named stdlib and needs to be writable
@@ -215,6 +220,7 @@ $(objpfx)tst-strtod6: $(libm)
$(objpfx)tst-strtod-nan-locale: $(libm)
tst-tls-atexit-lib.so-no-z-defs = yes
+test-dlclose-exit-race-helper.so-no-z-defs = yes
$(objpfx)tst-tls-atexit: $(shared-thread-library) $(libdl)
$(objpfx)tst-tls-atexit.out: $(objpfx)tst-tls-atexit-lib.so
diff --git a/stdlib/exit.c b/stdlib/exit.c
index b74f182..fec91aa 100644
--- a/stdlib/exit.c
+++ b/stdlib/exit.c
@@ -69,8 +69,7 @@ __run_exit_handlers (int status, struct exit_function_list **listp,
while (cur->idx > 0)
{
- const struct exit_function *const f =
- &cur->fns[--cur->idx];
+ struct exit_function *const f = &cur->fns[--cur->idx];
const uint64_t new_exitfn_called = __new_exitfn_called;
/* Unlock the list while we call a foreign function. */
@@ -99,6 +98,9 @@ __run_exit_handlers (int status, struct exit_function_list **listp,
atfct ();
break;
case ef_cxa:
+ /* To avoid dlclose/exit race calling cxafct twice (BZ 22180),
+ we must mark this function as ef_free. */
+ f->flavor = ef_free;
cxafct = f->func.cxa.fn;
#ifdef PTR_DEMANGLE
PTR_DEMANGLE (cxafct);
diff --git a/stdlib/test-dlclose-exit-race-helper.c b/stdlib/test-dlclose-exit-race-helper.c
new file mode 100644
index 0000000..fa76589
--- /dev/null
+++ b/stdlib/test-dlclose-exit-race-helper.c
@@ -0,0 +1,79 @@
+/* Helper for exit/dlclose race test (Bug 22180).
+ 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/>. */
+
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <semaphore.h>
+#include <unistd.h>
+#include <support/check.h>
+#include <support/xthread.h>
+
+/* Semaphore defined in executable to ensure we have a happens-before
+ between the first function starting and exit being called. */
+extern sem_t order1;
+
+/* Semaphore defined in executable to ensure we have a happens-before
+ between the second function starting and the first function returning. */
+extern sem_t order2;
+
+/* glibc function for registering DSO-specific exit functions. */
+extern int __cxa_atexit (void (*func) (void *), void *arg, void *dso_handle);
+
+/* Hidden compiler handle to this shared object. */
+extern void *__dso_handle __attribute__ ((__weak__));
+
+static void
+first (void *start)
+{
+ /* Let the exiting thread run. */
+ sem_post (&order1);
+
+ /* Wait for exiting thread to finish. */
+ sem_wait (&order2);
+
+ printf ("first\n");
+}
+
+static void
+second (void *start)
+{
+ /* We may be called from different threads.
+ This lock protects called. */
+ static pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;
+ static bool called = false;
+
+ xpthread_mutex_lock (&mtx);
+ if (called)
+ FAIL_EXIT1 ("second called twice!");
+
+ called = true;
+ xpthread_mutex_unlock (&mtx);
+
+ printf ("second\n");
+}
+
+
+__attribute__ ((constructor)) static void
+constructor (void)
+{
+ sem_init (&order1, 0, 0);
+ sem_init (&order2, 0, 0);
+ __cxa_atexit (second, NULL, __dso_handle);
+ __cxa_atexit (first, NULL, __dso_handle);
+}
diff --git a/stdlib/test-dlclose-exit-race.c b/stdlib/test-dlclose-exit-race.c
new file mode 100644
index 0000000..9ec294e
--- /dev/null
+++ b/stdlib/test-dlclose-exit-race.c
@@ -0,0 +1,80 @@
+/* Test for exit/dlclose race (Bug 22180).
+ 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". */
+
+/* This test verifies that when dlopen in one thread races against exit
+ in another thread, we don't call registered destructor twice.
+
+ Expected result:
+ second
+ first
+ ... clean termination
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <semaphore.h>
+#include <support/check.h>
+#include <support/xdlfcn.h>
+#include <support/xthread.h>
+
+/* Semaphore to ensure we have a happens-before between the first function
+ starting and exit being called. */
+sem_t order1;
+
+/* Semaphore to ensure we have a happens-before between the second function
+ starting and the first function returning. */
+sem_t order2;
+
+void *
+exit_thread (void *arg)
+{
+ /* Wait for the dlclose to start... */
+ sem_wait (&order1);
+ /* Then try to run the exit sequence which should call all
+ __cxa_atexit registered functions and in parallel with
+ the executing dlclose(). */
+ exit (0);
+}
+
+
+void
+last (void)
+{
+ /* Let dlclose thread proceed. */
+ sem_post (&order2);
+}
+
+int
+main (void)
+{
+ void *dso;
+ pthread_t thread;
+
+ atexit (last);
+
+ dso = xdlopen ("$ORIGIN/test-dlclose-exit-race-helper.so",
+ RTLD_NOW|RTLD_GLOBAL);
+ thread = xpthread_create (NULL, exit_thread, NULL);
+
+ xdlclose (dso);
+ xpthread_join (thread);
+
+ FAIL_EXIT1 ("Did not terminate via exit(0) in exit_thread() as expected.");
+}