[v3] Test case for BZ 19329
Commit Message
Test concurrent dlopen and pthread_create when the loaded
modules have TLS. This triggers dl-tls assertion failures
more reliably than the tst-stack4 test.
The dlopened module has 100 DT_NEEDED dependencies, the
number of concurrent threads created during dlopen depends
on filesystem speed and hardware.
Doing the test in a fork loop can make it more reliable.
v2:
- undef NDEBUG.
- join nop threads so at most 3 threads exist at a time.
- remove stack size setting (resource usage is no longer a concern).
- stop creating threads after dlopen observably finished.
- print the number of threads created for debugging.
v3:
- use the new test support code.
- better Makefile usage so modules are cleaned properly.
2016-12-13 Szabolcs Nagy <szabolcs.nagy@arm.com>
* nptl/Makefile (tests): Add tst-tls7.
(modules-names): Add tst-tls7mod, tst-tls7mod-dep.
* nptl/tst-tls7.c: New file.
* nptl/tst-tls7mod-dep.c: New file.
* nptl/tst-tls7mod.c: New file.
Comments
ping.
On 13/12/16 12:28, Szabolcs Nagy wrote:
> Test concurrent dlopen and pthread_create when the loaded
> modules have TLS. This triggers dl-tls assertion failures
> more reliably than the tst-stack4 test.
>
> The dlopened module has 100 DT_NEEDED dependencies, the
> number of concurrent threads created during dlopen depends
> on filesystem speed and hardware.
>
> Doing the test in a fork loop can make it more reliable.
>
> v2:
> - undef NDEBUG.
> - join nop threads so at most 3 threads exist at a time.
> - remove stack size setting (resource usage is no longer a concern).
> - stop creating threads after dlopen observably finished.
> - print the number of threads created for debugging.
>
> v3:
> - use the new test support code.
> - better Makefile usage so modules are cleaned properly.
>
> 2016-12-13 Szabolcs Nagy <szabolcs.nagy@arm.com>
>
> * nptl/Makefile (tests): Add tst-tls7.
> (modules-names): Add tst-tls7mod, tst-tls7mod-dep.
> * nptl/tst-tls7.c: New file.
> * nptl/tst-tls7mod-dep.c: New file.
> * nptl/tst-tls7mod.c: New file.
>
https://sourceware.org/ml/libc-alpha/2016-12/msg00456.html
ping 2.
i think v3 is safe and does not waste resources.
the only hack is the relaxed atomic operations, but i
wanted to avoid introducing additional barriers and the
correctness of the test does not depend on ordering.
if that's considered bad then those can be changed to
acquire/release atomics.
On 19/12/16 13:24, Szabolcs Nagy wrote:
> ping.
>
> On 13/12/16 12:28, Szabolcs Nagy wrote:
>> Test concurrent dlopen and pthread_create when the loaded
>> modules have TLS. This triggers dl-tls assertion failures
>> more reliably than the tst-stack4 test.
>>
>> The dlopened module has 100 DT_NEEDED dependencies, the
>> number of concurrent threads created during dlopen depends
>> on filesystem speed and hardware.
>>
>> Doing the test in a fork loop can make it more reliable.
>>
>> v2:
>> - undef NDEBUG.
>> - join nop threads so at most 3 threads exist at a time.
>> - remove stack size setting (resource usage is no longer a concern).
>> - stop creating threads after dlopen observably finished.
>> - print the number of threads created for debugging.
>>
>> v3:
>> - use the new test support code.
>> - better Makefile usage so modules are cleaned properly.
>>
>> 2016-12-13 Szabolcs Nagy <szabolcs.nagy@arm.com>
>>
>> * nptl/Makefile (tests): Add tst-tls7.
>> (modules-names): Add tst-tls7mod, tst-tls7mod-dep.
>> * nptl/tst-tls7.c: New file.
>> * nptl/tst-tls7mod-dep.c: New file.
>> * nptl/tst-tls7mod.c: New file.
>>
>
@@ -345,20 +345,24 @@ tests += tst-cancelx2 tst-cancelx3 tst-cancelx4 tst-cancelx5 \
tst-oncex3 tst-oncex4
ifeq ($(build-shared),yes)
tests += tst-atfork2 tst-tls3 tst-tls3-malloc tst-tls4 tst-tls5 tst-_res1 \
- tst-fini1 tst-stackguard1
+ tst-fini1 tst-stackguard1 tst-tls7
tests-nolibpthread += tst-fini1
ifeq ($(have-z-execstack),yes)
tests += tst-execstack
endif
endif
+one-hundred = $(foreach x,0 1 2 3 4 5 6 7 8 9, \
+ 0$x 1$x 2$x 3$x 4$x 5$x 6$x 7$x 8$x 9$x)
+tst-tls7mod-deps = $(one-hundred:%=tst-tls7mod-dep-%.so)
+
modules-names = tst-atfork2mod tst-tls3mod tst-tls4moda tst-tls4modb \
tst-tls5mod tst-tls5moda tst-tls5modb tst-tls5modc \
tst-tls5modd tst-tls5mode tst-tls5modf tst-stack4mod \
tst-_res1mod1 tst-_res1mod2 tst-execstack-mod tst-fini1mod \
- tst-join7mod
+ tst-join7mod tst-tls7mod tst-tls7mod-dep
extra-test-objs += $(addsuffix .os,$(strip $(modules-names))) \
- tst-cleanup4aux.o tst-cleanupx4aux.o
+ tst-cleanup4aux.o tst-cleanupx4aux.o $(tst-tls7mod-deps)
test-extras += $(modules-names) tst-cleanup4aux tst-cleanupx4aux
test-modules = $(addprefix $(objpfx),$(addsuffix .so,$(modules-names)))
@@ -563,6 +567,12 @@ $(objpfx)tst-tls5: $(objpfx)tst-tls5mod.so $(shared-thread-library)
LDFLAGS-tst-tls5 = $(no-as-needed)
LDFLAGS-tst-tls5mod.so = -Wl,-soname,tst-tls5mod.so
+$(objpfx)tst-tls7: $(libdl) $(shared-thread-library)
+$(objpfx)tst-tls7.out: $(objpfx)tst-tls7mod.so
+$(objpfx)tst-tls7mod.so: $(tst-tls7mod-deps:%=$(objpfx)%)
+$(tst-tls7mod-deps:%=$(objpfx)%): $(objpfx)tst-tls7mod-dep.so
+ cp -f $< $@
+
ifeq ($(build-shared),yes)
$(objpfx)tst-tls6.out: tst-tls6.sh $(objpfx)tst-tls5 \
$(objpfx)tst-tls5moda.so $(objpfx)tst-tls5modb.so \
new file mode 100644
@@ -0,0 +1,69 @@
+/* Test concurrent dlopen and pthread_create: BZ 19329.
+ Copyright (C) 2016 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 <dlfcn.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <atomic.h>
+
+#include <support/xthread.h>
+
+#define THREADS 10000
+
+static volatile int done;
+
+static void *
+start (void *a)
+{
+ if (dlopen ("tst-tls7mod.so", RTLD_LAZY) == NULL)
+ {
+ printf ("dlopen failed: %s\n", dlerror ());
+ exit (1);
+ }
+ atomic_store_relaxed (&done, 1);
+ return 0;
+}
+
+static void *
+nop (void *a)
+{
+ return 0;
+}
+
+static int
+do_test (void)
+{
+ pthread_t t1, t2;
+ int i;
+
+ /* Load a module with lots of dependencies and TLS. */
+ t1 = xpthread_create (0, start, 0);
+
+ /* Concurrently create lots of threads until dlopen is observably done. */
+ for (i = 0; i < THREADS && !atomic_load_relaxed (&done); i++)
+ {
+ t2 = xpthread_create (0, nop, 0);
+ xpthread_join (t2);
+ }
+
+ xpthread_join (t1);
+ printf ("threads created during dlopen: %d\n", i);
+ return 0;
+}
+
+#include <support/test-driver.c>
new file mode 100644
@@ -0,0 +1 @@
+int __thread x;
new file mode 100644
@@ -0,0 +1 @@
+int __thread x;