diff options
Diffstat (limited to 'nptl-pthread_kill-pthread_cancel-should-not-fail-aft.patch')
| -rw-r--r-- | nptl-pthread_kill-pthread_cancel-should-not-fail-aft.patch | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/nptl-pthread_kill-pthread_cancel-should-not-fail-aft.patch b/nptl-pthread_kill-pthread_cancel-should-not-fail-aft.patch new file mode 100644 index 0000000..7d1bc81 --- /dev/null +++ b/nptl-pthread_kill-pthread_cancel-should-not-fail-aft.patch @@ -0,0 +1,292 @@ +From 8af8456004edbab71f8903a60a3cae442cf6fe69 Mon Sep 17 00:00:00 2001 +From: Florian Weimer <fweimer@redhat.com> +Date: Mon, 13 Sep 2021 11:06:08 +0200 +Subject: [PATCH] nptl: pthread_kill, pthread_cancel should not fail after exit + (bug 19193) + +This closes one remaining race condition related to bug 12889: if +the thread already exited on the kernel side, returning ESRCH +is not correct because that error is reserved for the thread IDs +(pthread_t values) whose lifetime has ended. In case of a +kernel-side exit and a valid thread ID, no signal needs to be sent +and cancellation does not have an effect, so just return 0. + +sysdeps/pthread/tst-kill4.c triggers undefined behavior and is +removed with this commit. + +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> +--- + nptl/pthread_cancel.c | 9 +-- + nptl/pthread_kill.c | 7 ++- + sysdeps/pthread/Makefile | 5 +- + sysdeps/pthread/tst-kill4.c | 90 ----------------------------- + sysdeps/pthread/tst-pthread_cancel-exited.c | 45 +++++++++++++++ + sysdeps/pthread/tst-pthread_kill-exited.c | 46 +++++++++++++++ + 6 files changed, 106 insertions(+), 96 deletions(-) + delete mode 100644 sysdeps/pthread/tst-kill4.c + create mode 100644 sysdeps/pthread/tst-pthread_cancel-exited.c + create mode 100644 sysdeps/pthread/tst-pthread_kill-exited.c + +diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c +index 2bb523c..a8aa3b3 100644 +--- a/nptl/pthread_cancel.c ++++ b/nptl/pthread_cancel.c +@@ -61,10 +61,11 @@ __pthread_cancel (pthread_t th) + { + volatile struct pthread *pd = (volatile struct pthread *) th; + +- /* Make sure the descriptor is valid. */ +- if (INVALID_TD_P (pd)) +- /* Not a valid thread handle. */ +- return ESRCH; ++ if (pd->tid == 0) ++ /* The thread has already exited on the kernel side. Its outcome ++ (regular exit, other cancelation) has already been ++ determined. */ ++ return 0; + + static int init_sigcancel = 0; + if (atomic_load_relaxed (&init_sigcancel) == 0) +diff --git a/nptl/pthread_kill.c b/nptl/pthread_kill.c +index f79a2b2..5d4c86f 100644 +--- a/nptl/pthread_kill.c ++++ b/nptl/pthread_kill.c +@@ -46,7 +46,12 @@ __pthread_kill_internal (pthread_t threadid, int signo) + ? INTERNAL_SYSCALL_ERRNO (val) : 0); + } + else +- val = ESRCH; ++ /* The kernel reports that the thread has exited. POSIX specifies ++ the ESRCH error only for the case when the lifetime of a thread ++ ID has ended, but calling pthread_kill on such a thread ID is ++ undefined in glibc. Therefore, do not treat kernel thread exit ++ as an error. */ ++ val = 0; + + return val; + } +diff --git a/sysdeps/pthread/Makefile b/sysdeps/pthread/Makefile +index 42f9fc5..dedfa0d 100644 +--- a/sysdeps/pthread/Makefile ++++ b/sysdeps/pthread/Makefile +@@ -89,7 +89,7 @@ tests += tst-cnd-basic tst-mtx-trylock tst-cnd-broadcast \ + tst-join8 tst-join9 tst-join10 tst-join11 tst-join12 tst-join13 \ + tst-join14 tst-join15 \ + tst-key1 tst-key2 tst-key3 tst-key4 \ +- tst-kill1 tst-kill2 tst-kill3 tst-kill4 tst-kill5 tst-kill6 \ ++ tst-kill1 tst-kill2 tst-kill3 tst-kill5 tst-kill6 \ + tst-locale1 tst-locale2 \ + tst-memstream \ + tst-mutex-errorcheck tst-mutex1 tst-mutex2 tst-mutex3 tst-mutex4 \ +@@ -118,6 +118,9 @@ tests += tst-cnd-basic tst-mtx-trylock tst-cnd-broadcast \ + tst-unload \ + tst-unwind-thread \ + tst-pt-vfork1 tst-pt-vfork2 tst-vfork1x tst-vfork2x \ ++ tst-pthread_cancel-exited \ ++ tst-pthread_kill-exited \ ++ # tests + + tests-time64 := \ + tst-abstime-time64 \ +diff --git a/sysdeps/pthread/tst-kill4.c b/sysdeps/pthread/tst-kill4.c +deleted file mode 100644 +index 222ceb7..0000000 +--- a/sysdeps/pthread/tst-kill4.c ++++ /dev/null +@@ -1,90 +0,0 @@ +-/* Copyright (C) 2003-2021 Free Software Foundation, Inc. +- This file is part of the GNU C Library. +- Contributed by Ulrich Drepper <drepper@redhat.com>, 2003. +- +- 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 <errno.h> +-#include <pthread.h> +-#include <signal.h> +-#include <stdio.h> +-#include <stdlib.h> +-#include <unistd.h> +- +- +-static void * +-tf (void *a) +-{ +- return NULL; +-} +- +- +-int +-do_test (void) +-{ +- pthread_attr_t at; +- if (pthread_attr_init (&at) != 0) +- { +- puts ("attr_create failed"); +- exit (1); +- } +- +- /* Limit thread stack size, because if it is too large, pthread_join +- will free it immediately rather than put it into stack cache. */ +- if (pthread_attr_setstacksize (&at, 2 * 1024 * 1024) != 0) +- { +- puts ("setstacksize failed"); +- exit (1); +- } +- +- pthread_t th; +- if (pthread_create (&th, &at, tf, NULL) != 0) +- { +- puts ("create failed"); +- exit (1); +- } +- +- pthread_attr_destroy (&at); +- +- if (pthread_join (th, NULL) != 0) +- { +- puts ("join failed"); +- exit (1); +- } +- +- /* The following only works because we assume here something about +- the implementation. Namely, that the memory allocated for the +- thread descriptor is not going away, that the TID field is +- cleared and therefore the signal is sent to process 0, and that +- we can savely assume there is no other process with this ID at +- that time. */ +- int e = pthread_kill (th, 0); +- if (e == 0) +- { +- puts ("pthread_kill succeeded"); +- exit (1); +- } +- if (e != ESRCH) +- { +- puts ("pthread_kill didn't return ESRCH"); +- exit (1); +- } +- +- return 0; +-} +- +- +-#define TEST_FUNCTION do_test () +-#include "../test-skeleton.c" +diff --git a/sysdeps/pthread/tst-pthread_cancel-exited.c b/sysdeps/pthread/tst-pthread_cancel-exited.c +new file mode 100644 +index 0000000..811c9be +--- /dev/null ++++ b/sysdeps/pthread/tst-pthread_cancel-exited.c +@@ -0,0 +1,45 @@ ++/* Test that pthread_kill succeeds for an exited thread. ++ 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 verifies that pthread_kill returns 0 (and not ESRCH) for ++ a thread that has exited on the kernel side. */ ++ ++#include <stddef.h> ++#include <support/support.h> ++#include <support/xthread.h> ++ ++static void * ++noop_thread (void *closure) ++{ ++ return NULL; ++} ++ ++static int ++do_test (void) ++{ ++ pthread_t thr = xpthread_create (NULL, noop_thread, NULL); ++ ++ support_wait_for_thread_exit (); ++ ++ xpthread_cancel (thr); ++ xpthread_join (thr); ++ ++ return 0; ++} ++ ++#include <support/test-driver.c> +diff --git a/sysdeps/pthread/tst-pthread_kill-exited.c b/sysdeps/pthread/tst-pthread_kill-exited.c +new file mode 100644 +index 0000000..7575fb6 +--- /dev/null ++++ b/sysdeps/pthread/tst-pthread_kill-exited.c +@@ -0,0 +1,46 @@ ++/* Test that pthread_kill succeeds for an exited thread. ++ 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 verifies that pthread_kill returns 0 (and not ESRCH) for ++ a thread that has exited on the kernel side. */ ++ ++#include <signal.h> ++#include <stddef.h> ++#include <support/support.h> ++#include <support/xthread.h> ++ ++static void * ++noop_thread (void *closure) ++{ ++ return NULL; ++} ++ ++static int ++do_test (void) ++{ ++ pthread_t thr = xpthread_create (NULL, noop_thread, NULL); ++ ++ support_wait_for_thread_exit (); ++ ++ xpthread_kill (thr, SIGUSR1); ++ xpthread_join (thr); ++ ++ return 0; ++} ++ ++#include <support/test-driver.c> +-- +1.8.3.1 + |