[v2,07/14] elf: Add 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
nptl/tst-stack4 test.
The dlopened module has 100 DT_NEEDED dependencies with TLS, they were
reused from an existing TLS test. The number of created threads during
dlopen depends on filesystem speed and hardware, but at most 3 threads
are alive at a time to limit resource usage.
---
v5:
- moved from nptl/ to elf/
- use many tls modules from another test (affects the timing a bit as
these need more relocation processing, but still detects the race)
- use xdlopen
- use stdatomic.h
- moved from tests-internal back to tests
- use acq/rel atomics instead of relaxed, this works too and cleaner.
- moved after bug fix patch.
v4:
- rebased, updated copyright year.
- moved to tests-internal because of <atomic.h>
v3:
- use the new test support code.
- better Makefile usage so modules are cleaned properly.
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.
---
elf/Makefile | 9 ++++--
elf/tst-tls21.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
elf/tst-tls21mod.c | 1 +
3 files changed, 76 insertions(+), 2 deletions(-)
create mode 100644 elf/tst-tls21.c
create mode 100644 elf/tst-tls21mod.c
Comments
On 13/04/2021 05:19, Szabolcs Nagy via Libc-alpha wrote:
> Test concurrent dlopen and pthread_create when the loaded modules have
> TLS. This triggers dl-tls assertion failures more reliably than the
> nptl/tst-stack4 test.
>
> The dlopened module has 100 DT_NEEDED dependencies with TLS, they were
> reused from an existing TLS test. The number of created threads during
> dlopen depends on filesystem speed and hardware, but at most 3 threads
> are alive at a time to limit resource usage.
>
> ---
> v5:
> - moved from nptl/ to elf/
> - use many tls modules from another test (affects the timing a bit as
> these need more relocation processing, but still detects the race)
> - use xdlopen
> - use stdatomic.h
> - moved from tests-internal back to tests
> - use acq/rel atomics instead of relaxed, this works too and cleaner.
> - moved after bug fix patch.
>
> v4:
> - rebased, updated copyright year.
> - moved to tests-internal because of <atomic.h>
>
> v3:
> - use the new test support code.
> - better Makefile usage so modules are cleaned properly.
>
> 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.
LGTM, thanks.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> ---
> elf/Makefile | 9 ++++--
> elf/tst-tls21.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
> elf/tst-tls21mod.c | 1 +
> 3 files changed, 76 insertions(+), 2 deletions(-)
> create mode 100644 elf/tst-tls21.c
> create mode 100644 elf/tst-tls21mod.c
>
> diff --git a/elf/Makefile b/elf/Makefile
> index b1344f1133..e9377608eb 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -223,7 +223,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
> tst-single_threaded tst-single_threaded-pthread \
> tst-tls-ie tst-tls-ie-dlmopen argv0test \
> tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
> - tst-tls20
> + tst-tls20 tst-tls21
> # reldep9
> tests-internal += loadtest unload unload2 circleload1 \
> neededtest neededtest2 neededtest3 neededtest4 \
Ok.
> @@ -345,7 +345,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
> libmarkermod2-1 libmarkermod2-2 \
> libmarkermod3-1 libmarkermod3-2 libmarkermod3-3 \
> libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \
> - tst-tls20mod-bad
> + tst-tls20mod-bad tst-tls21mod
>
> # Most modules build with _ISOMAC defined, but those filtered out
> # depend on internal headers.
Ok.
> @@ -1932,3 +1932,8 @@ tst-tls20mod-bad.so-no-z-defs = yes
> $(objpfx)tst-tls20: $(libdl) $(shared-thread-library)
> $(objpfx)tst-tls20.out: $(objpfx)tst-tls20mod-bad.so \
> $(tst-tls-many-dynamic-modules:%=$(objpfx)%.so)
> +
> +# Reuses tst-tls-many-dynamic-modules
> +$(objpfx)tst-tls21: $(libdl) $(shared-thread-library)
> +$(objpfx)tst-tls21.out: $(objpfx)tst-tls21mod.so
> +$(objpfx)tst-tls21mod.so: $(tst-tls-many-dynamic-modules:%=$(objpfx)%.so)
Ok.
> diff --git a/elf/tst-tls21.c b/elf/tst-tls21.c
> new file mode 100644
> index 0000000000..560bf5813a
> --- /dev/null
> +++ b/elf/tst-tls21.c
> @@ -0,0 +1,68 @@
> +/* Test concurrent dlopen and pthread_create: BZ 19329.
> + Copyright (C) 2021 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 <stdatomic.h>
> +#include <support/xdlfcn.h>
> +#include <support/xthread.h>
> +
> +#define THREADS 10000
> +
> +static atomic_int done;
> +
> +static void *
> +start (void *a)
> +{
> + /* Load a module with many dependencies that each have TLS. */
> + xdlopen ("tst-tls21mod.so", RTLD_LAZY);
> + atomic_store_explicit (&done, 1, memory_order_release);
> + 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; i++)
> + {
> + if (atomic_load_explicit (&done, memory_order_acquire) != 0)
> + break;
> + 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>
Ok,
> diff --git a/elf/tst-tls21mod.c b/elf/tst-tls21mod.c
> new file mode 100644
> index 0000000000..206ece4fb3
> --- /dev/null
> +++ b/elf/tst-tls21mod.c
> @@ -0,0 +1 @@
> +int __thread x;
>
Ok.
@@ -223,7 +223,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
tst-single_threaded tst-single_threaded-pthread \
tst-tls-ie tst-tls-ie-dlmopen argv0test \
tst-glibc-hwcaps tst-glibc-hwcaps-prepend tst-glibc-hwcaps-mask \
- tst-tls20
+ tst-tls20 tst-tls21
# reldep9
tests-internal += loadtest unload unload2 circleload1 \
neededtest neededtest2 neededtest3 neededtest4 \
@@ -345,7 +345,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
libmarkermod2-1 libmarkermod2-2 \
libmarkermod3-1 libmarkermod3-2 libmarkermod3-3 \
libmarkermod4-1 libmarkermod4-2 libmarkermod4-3 libmarkermod4-4 \
- tst-tls20mod-bad
+ tst-tls20mod-bad tst-tls21mod
# Most modules build with _ISOMAC defined, but those filtered out
# depend on internal headers.
@@ -1932,3 +1932,8 @@ tst-tls20mod-bad.so-no-z-defs = yes
$(objpfx)tst-tls20: $(libdl) $(shared-thread-library)
$(objpfx)tst-tls20.out: $(objpfx)tst-tls20mod-bad.so \
$(tst-tls-many-dynamic-modules:%=$(objpfx)%.so)
+
+# Reuses tst-tls-many-dynamic-modules
+$(objpfx)tst-tls21: $(libdl) $(shared-thread-library)
+$(objpfx)tst-tls21.out: $(objpfx)tst-tls21mod.so
+$(objpfx)tst-tls21mod.so: $(tst-tls-many-dynamic-modules:%=$(objpfx)%.so)
new file mode 100644
@@ -0,0 +1,68 @@
+/* Test concurrent dlopen and pthread_create: BZ 19329.
+ Copyright (C) 2021 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 <stdatomic.h>
+#include <support/xdlfcn.h>
+#include <support/xthread.h>
+
+#define THREADS 10000
+
+static atomic_int done;
+
+static void *
+start (void *a)
+{
+ /* Load a module with many dependencies that each have TLS. */
+ xdlopen ("tst-tls21mod.so", RTLD_LAZY);
+ atomic_store_explicit (&done, 1, memory_order_release);
+ 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; i++)
+ {
+ if (atomic_load_explicit (&done, memory_order_acquire) != 0)
+ break;
+ 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;