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154 lines
5.2 KiB
154 lines
5.2 KiB
commit 40bade26d5bcbda3d21fb598c5063d9df62de966 |
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Author: Florian Weimer <fweimer@redhat.com> |
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Date: Fri Oct 1 18:16:41 2021 +0200 |
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nptl: pthread_kill must send signals to a specific thread [BZ #28407] |
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The choice between the kill vs tgkill system calls is not just about |
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the TID reuse race, but also about whether the signal is sent to the |
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whole process (and any thread in it) or to a specific thread. |
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This was caught by the openposix test suite: |
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LTP: openposix test suite - FAIL: SIGUSR1 is member of new thread pendingset. |
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<https://gitlab.com/cki-project/kernel-tests/-/issues/764> |
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Fixes commit 526c3cf11ee9367344b6b15d669e4c3cb461a2be ("nptl: Fix race |
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between pthread_kill and thread exit (bug 12889)"). |
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Reviewed-by: Carlos O'Donell <carlos@redhat.com> |
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Tested-by: Carlos O'Donell <carlos@redhat.com> |
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(cherry picked from commit eae81d70574e923ce3c59078b8df857ae192efa6) |
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diff --git a/nptl/pthread_kill.c b/nptl/pthread_kill.c |
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index a44dc8f2d9baa925..35bf1f973eaeda90 100644 |
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--- a/nptl/pthread_kill.c |
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+++ b/nptl/pthread_kill.c |
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@@ -40,7 +40,7 @@ __pthread_kill_implementation (pthread_t threadid, int signo, int no_tid) |
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below. POSIX only guarantees delivery of a single signal, |
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which may not be the right one.) */ |
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pid_t tid = INTERNAL_SYSCALL_CALL (gettid); |
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- int ret = INTERNAL_SYSCALL_CALL (kill, tid, signo); |
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+ int ret = INTERNAL_SYSCALL_CALL (tgkill, __getpid (), tid, signo); |
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return INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO (ret) : 0; |
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} |
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@@ -59,8 +59,6 @@ __pthread_kill_implementation (pthread_t threadid, int signo, int no_tid) |
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ret = no_tid; |
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else |
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{ |
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- /* Using tgkill is a safety measure. pd->exit_lock ensures that |
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- the target thread cannot exit. */ |
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ret = INTERNAL_SYSCALL_CALL (tgkill, __getpid (), pd->tid, signo); |
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ret = INTERNAL_SYSCALL_ERROR_P (ret) ? INTERNAL_SYSCALL_ERRNO (ret) : 0; |
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} |
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diff --git a/sysdeps/pthread/Makefile b/sysdeps/pthread/Makefile |
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index d4bd2d4e3ee6a496..0af9c59b425aefb1 100644 |
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--- a/sysdeps/pthread/Makefile |
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+++ b/sysdeps/pthread/Makefile |
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@@ -121,6 +121,7 @@ tests += tst-cnd-basic tst-mtx-trylock tst-cnd-broadcast \ |
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tst-pthread-setuid-loop \ |
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tst-pthread_cancel-exited \ |
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tst-pthread_cancel-select-loop \ |
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+ tst-pthread-raise-blocked-self \ |
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tst-pthread_kill-exited \ |
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tst-pthread_kill-exiting \ |
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# tests |
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diff --git a/sysdeps/pthread/tst-pthread-raise-blocked-self.c b/sysdeps/pthread/tst-pthread-raise-blocked-self.c |
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new file mode 100644 |
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index 0000000000000000..128e1a6071c0b15f |
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--- /dev/null |
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+++ b/sysdeps/pthread/tst-pthread-raise-blocked-self.c |
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@@ -0,0 +1,92 @@ |
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+/* Test that raise sends signal to current thread even if blocked. |
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+ Copyright (C) 2021 Free Software Foundation, Inc. |
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+ This file is part of the GNU C Library. |
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+ |
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+ The GNU C Library is free software; you can redistribute it and/or |
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+ modify it under the terms of the GNU Lesser General Public |
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+ License as published by the Free Software Foundation; either |
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+ version 2.1 of the License, or (at your option) any later version. |
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+ |
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+ The GNU C Library is distributed in the hope that it will be useful, |
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of |
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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+ Lesser General Public License for more details. |
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+ |
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+ You should have received a copy of the GNU Lesser General Public |
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+ License along with the GNU C Library; if not, see |
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+ <https://www.gnu.org/licenses/>. */ |
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+ |
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+#include <signal.h> |
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+#include <support/check.h> |
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+#include <support/xsignal.h> |
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+#include <support/xthread.h> |
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+#include <pthread.h> |
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+#include <unistd.h> |
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+ |
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+/* Used to create a dummy thread ID distinct from all other thread |
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+ IDs. */ |
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+static void * |
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+noop (void *ignored) |
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+{ |
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+ return NULL; |
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+} |
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+ |
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+static volatile pthread_t signal_thread; |
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+ |
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+static void |
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+signal_handler (int signo) |
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+{ |
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+ signal_thread = pthread_self (); |
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+} |
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+ |
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+/* Used to ensure that waiting_thread has launched and can accept |
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+ signals. */ |
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+static pthread_barrier_t barrier; |
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+ |
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+static void * |
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+waiting_thread (void *ignored) |
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+{ |
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+ xpthread_barrier_wait (&barrier); |
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+ pause (); |
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+ return NULL; |
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+} |
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+ |
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+static int |
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+do_test (void) |
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+{ |
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+ xsignal (SIGUSR1, signal_handler); |
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+ xpthread_barrier_init (&barrier, NULL, 2); |
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+ |
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+ /* Distinct thread ID value to */ |
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+ pthread_t dummy = xpthread_create (NULL, noop, NULL); |
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+ signal_thread = dummy; |
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+ |
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+ pthread_t helper = xpthread_create (NULL, waiting_thread, NULL); |
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+ |
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+ /* Make sure that the thread is running. */ |
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+ xpthread_barrier_wait (&barrier); |
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+ |
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+ /* Block signals on this thread. */ |
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+ sigset_t set; |
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+ sigfillset (&set); |
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+ xpthread_sigmask (SIG_BLOCK, &set, NULL); |
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+ |
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+ /* Send the signal to this thread. It must not be delivered. */ |
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+ raise (SIGUSR1); |
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+ TEST_VERIFY (signal_thread == dummy); |
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+ |
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+ /* Wait a bit to give a chance for signal delivery (increases |
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+ chances of failure with bug 28407). */ |
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+ usleep (50 * 1000); |
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+ |
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+ /* Unblocking should cause synchronous delivery of the signal. */ |
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+ xpthread_sigmask (SIG_UNBLOCK, &set, NULL); |
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+ TEST_VERIFY (signal_thread == pthread_self ()); |
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+ |
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+ xpthread_cancel (helper); |
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+ xpthread_join (helper); |
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+ xpthread_join (dummy); |
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+ return 0; |
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+} |
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+ |
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+#include <support/test-driver.c>
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