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author | Florian Weimer <fweimer@redhat.com> | 2021-09-13 11:06:08 +0200 |
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committer | Florian Weimer <fweimer@redhat.com> | 2021-09-13 11:06:08 +0200 |
commit | 526c3cf11ee9367344b6b15d669e4c3cb461a2be (patch) | |
tree | 428aa0c50880ee5001732622b0afe94ba7e113d9 /sysdeps/pthread/tst-pthread_cancel-select-loop.c | |
parent | 8af8456004edbab71f8903a60a3cae442cf6fe69 (diff) | |
download | glibc-526c3cf11ee9367344b6b15d669e4c3cb461a2be.tar.gz glibc-526c3cf11ee9367344b6b15d669e4c3cb461a2be.tar.xz glibc-526c3cf11ee9367344b6b15d669e4c3cb461a2be.zip |
nptl: Fix race between pthread_kill and thread exit (bug 12889)
A new thread exit lock and flag are introduced. They are used to detect that the thread is about to exit or has exited in __pthread_kill_internal, and the signal is not sent in this case. The test sysdeps/pthread/tst-pthread_cancel-select-loop.c is derived from a downstream test originally written by Marek Polacek. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/pthread/tst-pthread_cancel-select-loop.c')
-rw-r--r-- | sysdeps/pthread/tst-pthread_cancel-select-loop.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/sysdeps/pthread/tst-pthread_cancel-select-loop.c b/sysdeps/pthread/tst-pthread_cancel-select-loop.c new file mode 100644 index 0000000000..a62087589c --- /dev/null +++ b/sysdeps/pthread/tst-pthread_cancel-select-loop.c @@ -0,0 +1,87 @@ +/* Test that pthread_cancel succeeds during thread exit. + 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 + <https://www.gnu.org/licenses/>. */ + +/* This test tries to trigger an internal race condition in + pthread_cancel, where the cancellation signal is sent after the + thread has begun the cancellation process. This can result in a + spurious ESRCH error. For the original bug 12889, the window is + quite small, so the bug was not reproduced in every run. */ + +#include <stdbool.h> +#include <stddef.h> +#include <support/check.h> +#include <support/xthread.h> +#include <support/xunistd.h> +#include <sys/select.h> +#include <unistd.h> + +/* Set to true by timeout_thread_function when the test should + terminate. */ +static bool timeout; + +static void * +timeout_thread_function (void *unused) +{ + usleep (5 * 1000 * 1000); + __atomic_store_n (&timeout, true, __ATOMIC_RELAXED); + return NULL; +} + +/* Used for blocking the select function below. */ +static int pipe_fds[2]; + +static void * +canceled_thread_function (void *unused) +{ + while (true) + { + fd_set rfs; + fd_set wfs; + fd_set efs; + FD_ZERO (&rfs); + FD_ZERO (&wfs); + FD_ZERO (&efs); + FD_SET (pipe_fds[0], &rfs); + + /* If the cancellation request is recognized early, the thread + begins exiting while the cancellation signal arrives. */ + select (FD_SETSIZE, &rfs, &wfs, &efs, NULL); + } + return NULL; +} + +static int +do_test (void) +{ + xpipe (pipe_fds); + pthread_t thr_timeout = xpthread_create (NULL, timeout_thread_function, NULL); + + while (!__atomic_load_n (&timeout, __ATOMIC_RELAXED)) + { + pthread_t thr = xpthread_create (NULL, canceled_thread_function, NULL); + xpthread_cancel (thr); + TEST_VERIFY (xpthread_join (thr) == PTHREAD_CANCELED); + } + + xpthread_join (thr_timeout); + xclose (pipe_fds[0]); + xclose (pipe_fds[1]); + return 0; +} + +#include <support/test-driver.c> |