From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Wang Date: Tue, 24 Sep 2019 18:58:01 +0800 Subject: [LTP] [PATCH v3] fzsync: revoke thread_b if parent hits an accidental break Message-ID: <20190924105801.7616-1-liwang@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it We shouldn't rely entirely on the pair->exit flag in tst_fzsync_pair_cleanup() since there is possible to call tst_brk() at anyplace of thread_a, that will lead to timeout eventually because of thread_b(tst_fzsync_wait_b) fall into an infinite(no explicit condition to exit) loop. Thread_a path trace: tst_brk() cleanup() tst_fzsync_pair_cleanup() SAFE_PTHREAD_JOIN(pair->thread_b, NULL) #Or pthread_cancel(pair->thread_b) We fix the problem via a way to kill thread_b with pthread_cancel. Work-around: [commit 2e74d996: Check recvmmsg exists before entering fuzzy loop] Signed-off-by: Li Wang Cc: Richard Palethorpe Cc: Cyril Hrubis --- Notes: Patch V2: http://lists.linux.it/pipermail/ltp/2019-January/010489.html Patch V1: http://lists.linux.it/pipermail/ltp/2019-January/010438.html include/tst_fuzzy_sync.h | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/include/tst_fuzzy_sync.h b/include/tst_fuzzy_sync.h index f9a1947c7..152f779cb 100644 --- a/include/tst_fuzzy_sync.h +++ b/include/tst_fuzzy_sync.h @@ -63,6 +63,7 @@ #include #include #include +#include #include "tst_atomic.h" #include "tst_timer.h" #include "tst_safe_pthread.h" @@ -218,9 +219,13 @@ static void tst_fzsync_pair_init(struct tst_fzsync_pair *pair) static void tst_fzsync_pair_cleanup(struct tst_fzsync_pair *pair) { if (pair->thread_b) { - tst_atomic_store(1, &pair->exit); - SAFE_PTHREAD_JOIN(pair->thread_b, NULL); - pair->thread_b = 0; + if (pair->exit == 1) { + SAFE_PTHREAD_JOIN(pair->thread_b, NULL); + pair->thread_b = 0; + } else { + pthread_cancel(pair->thread_b); + pair->thread_b = 0; + } } } @@ -271,8 +276,11 @@ static void tst_fzsync_pair_reset(struct tst_fzsync_pair *pair, pair->a_cntr = 0; pair->b_cntr = 0; pair->exit = 0; - if (run_b) + if (run_b) { + pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL); + pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL); SAFE_PTHREAD_CREATE(&pair->thread_b, 0, run_b, 0); + } pair->exec_time_start = (float)tst_timeout_remaining(); } -- 2.20.1