glibc/sysdeps/pthread/tst-join7.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

47 lines
1.8 KiB
C

/* Verify that TLS access in separate thread in a dlopened library does not
deadlock.
Copyright (C) 2015-2022 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
<https://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"