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b=7cY4XRQAwuFhxhDPAj0vlBOCk616pod2x2Wir1uvHy1Yemka80tLnd4KjXvF1lWHsQ2rg7 SI821Et7WBVG9zAw== Received: from g78 (unknown [10.163.28.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 906B22C142; Wed, 6 Sep 2023 10:38:30 +0000 (UTC) References: <20230830155548.9402-1-andrea.cervesato@suse.de> User-agent: mu4e 1.10.6; emacs 29.1 From: Richard Palethorpe To: Andrea Cervesato Date: Wed, 06 Sep 2023 10:02:35 +0100 Organization: Linux Private Site In-reply-to: <20230830155548.9402-1-andrea.cervesato@suse.de> Message-ID: <87v8cnegd7.fsf@suse.de> MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 1.0.1 at in-7.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH v1] Refactor exit_group01 using new API X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: rpalethorpe@suse.de Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hello, Andrea Cervesato writes: > From: Andrea Cervesato > > We provided a different approach to exit_group() testing, spawning > multiple threads inside the child and checking if they get killed with > the parent process. > > Signed-off-by: Andrea Cervesato > --- > testcases/kernel/syscalls/exit_group/Makefile | 2 + > .../kernel/syscalls/exit_group/exit_group01.c | 137 +++++++++++------- > 2 files changed, 85 insertions(+), 54 deletions(-) > > diff --git a/testcases/kernel/syscalls/exit_group/Makefile b/testcases/kernel/syscalls/exit_group/Makefile > index 1273a4e9c..adbac3c51 100644 > --- a/testcases/kernel/syscalls/exit_group/Makefile > +++ b/testcases/kernel/syscalls/exit_group/Makefile > @@ -3,6 +3,8 @@ > > top_srcdir ?= ../../../.. > > +exit_group01: CFLAGS+=-pthread > + > include $(top_srcdir)/include/mk/testcases.mk > > include $(top_srcdir)/include/mk/generic_leaf_target.mk > diff --git a/testcases/kernel/syscalls/exit_group/exit_group01.c b/testcases/kernel/syscalls/exit_group/exit_group01.c > index 5bf5b0218..0ed008115 100644 > --- a/testcases/kernel/syscalls/exit_group/exit_group01.c > +++ b/testcases/kernel/syscalls/exit_group/exit_group01.c > @@ -1,68 +1,97 @@ > -/****************************************************************************** > - * Copyright (c) Crackerjack Project., 2007 * > - * Ported to LTP by Manas Kumar Nayak * > - * Copyright (C) 2015 Cyril Hrubis * > - * * > - * This program is free software; you can redistribute it and/or modify * > - * it under the terms of the GNU General Public License as published by * > - * the Free Software Foundation; either version 2 of the License, or * > - * (at your option) any later version. * > - * * > - * This program 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 General Public License for more details. * > - * * > - * You should have received a copy of the GNU General Public License * > - * along with this program; if not, write to the Free Software Foundation, * > - * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * > - * * > - ******************************************************************************/ > - > -#include > -#include > -#include > -#include > - > -#include "test.h" > -#include "safe_macros.h" > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Copyright (c) Crackerjack Project., 2007 > + * Ported to LTP by Manas Kumar Nayak > + * Copyright (c) 2015 Linux Test Project > + * Copyright (C) 2015 Cyril Hrubis > + * Copyright (C) 2023 SUSE LLC Andrea Cervesato > + */ > + > +/*\ > + * [Description] > + * > + * This test checks if exit_group() correctly ends a spawned child and all its > + * running threads. > + */ > + > +#include > +#include "tst_safe_pthread.h" > +#include "tst_test.h" > #include "lapi/syscalls.h" > > -char *TCID = "exit_group01"; > -int testno; > -int TST_TOTAL = 1; > +/* gittid is not defined by glibc */ > +#define gettid() syscall(SYS_gettid) > + > +#define THREADS_NUM 10 > > -static void verify_exit_group(void) > +static pid_t *tids; > + > +static void *worker(void *arg) > { > - pid_t cpid, w; > - int status; > + int i = *((int *)arg); > > - cpid = fork(); > - if (cpid == -1) > - tst_brkm(TFAIL | TERRNO, NULL, "fork failed"); > + tids[i] = gettid(); > > - if (cpid == 0) { > - TEST(tst_syscall(__NR_exit_group, 4)); > - } else { > - w = SAFE_WAIT(NULL, &status); > - > - if (WIFEXITED(status) && (WEXITSTATUS(status) == 4)) { > - tst_resm(TPASS, "exit_group() succeeded"); > - } else { > - tst_resm(TFAIL | TERRNO, > - "exit_group() failed (wait status = %d)", w); > - } > + TST_CHECKPOINT_WAKE(0); > + pause(); > + > + return arg; > +} > + > +static void spawn_threads(void) > +{ > + pthread_t threads[THREADS_NUM]; > + > + for (int i = 0; i < THREADS_NUM; i++) { > + SAFE_PTHREAD_CREATE(&threads[i], NULL, worker, (void *)&i); > + TST_CHECKPOINT_WAIT(0); > } > } > > -int main(int ac, char **av) > +static void run(void) > { > - int lc; > + pid_t pid; > + int status; > > - tst_parse_opts(ac, av, NULL, NULL); > + pid = SAFE_FORK(); > + if (!pid) { > + spawn_threads(); > > - for (lc = 0; TEST_LOOPING(lc); lc++) > - verify_exit_group(); > + TEST(tst_syscall(__NR_exit_group, 4)); > + if (TST_RET == -1) > + tst_brk(TBROK | TERRNO, "exit_group() error"); > + > + return; > + } > + > + SAFE_WAITPID(pid, &status, 0); > + > + TST_EXP_EXPR(WIFEXITED(status) && WEXITSTATUS(status) == 4, > + "exit_group() succeeded"); > + > + for (int i = 0; i < THREADS_NUM; i++) > + TST_EXP_FAIL(kill(tids[i], 0), ESRCH); I'm not sure if there is a race condition here because 1. I can't find a synchronisation mechanism when the kernel sends the kill signal to the children. It just sets the signal then schedules them. 2. I can't see a clear way that wait{pid,id} would wait for a process and its children. In fact I'm not sure if all the children of the thread group leader need (or can be) to be waited on (you may need __WALL in options). Could you try waiting on the idividual tids[] and then the pid? I haven't seen the test fail, but the main test task (sleeping in waitpid) probably gets scheduled after the child thread tasks. However this doesn't seem like behaviour we can rely on. > +} > + > +static void setup(void) > +{ > + tids = SAFE_MMAP( > + NULL, > + sizeof(pid_t) * THREADS_NUM, > + PROT_READ | PROT_WRITE, > + MAP_SHARED | MAP_ANONYMOUS, > + -1, 0); > +} > > - tst_exit(); > +static void cleanup(void) > +{ > + SAFE_MUNMAP(tids, sizeof(pid_t) * THREADS_NUM); > } > + > +static struct tst_test test = { > + .setup = setup, > + .cleanup = cleanup, > + .test_all = run, > + .forks_child = 1, > + .needs_checkpoints = 1, > +}; > -- > 2.35.3 -- Thank you, Richard. -- Mailing list info: https://lists.linux.it/listinfo/ltp