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Diffstat (limited to 'nptl/tst-join7.c')
-rw-r--r-- | nptl/tst-join7.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/nptl/tst-join7.c b/nptl/tst-join7.c new file mode 100644 index 0000000000..439d0fc9bb --- /dev/null +++ b/nptl/tst-join7.c @@ -0,0 +1,46 @@ +/* Verify that TLS access in separate thread in a dlopened library does not + deadlock. + Copyright (C) 2015 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> + +/* When one dynamically loads a module, which spawns a thread to perform some + activities, it could be possible that TLS storage is accessed for the first + time in that thread. This results in an allocation request within the + thread, which could result in an attempt to take the rtld load_lock. This + is a problem because it would then deadlock with the dlopen (which owns the + lock), if the main thread is waiting for the spawned thread to exit. We can + at least ensure that this problem does not occur due to accesses within + libc.so, by marking TLS variables within libc.so as IE. The problem of an + arbitrary variable being accessed and constructed within such a thread still + exists but this test case does not verify that. */ + +int +do_test (void) +{ + void *f = dlopen ("tst-join7mod.so", RTLD_NOW | RTLD_GLOBAL); + if (f) + dlclose (f); + else + return 1; + + return 0; +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" |