From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:36267 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751152AbdAQEjl (ORCPT ); Mon, 16 Jan 2017 23:39:41 -0500 Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 4D616ABDF for ; Tue, 17 Jan 2017 04:39:40 +0000 (UTC) From: jeffm@suse.com Subject: [PATCH 1/3] xfs_repair: clear pthread_t when pthread_create fails Date: Mon, 16 Jan 2017 23:39:31 -0500 Message-Id: <1484627973-11535-2-git-send-email-jeffm@suse.com> In-Reply-To: <1484627973-11535-1-git-send-email-jeffm@suse.com> References: <1484627973-11535-1-git-send-email-jeffm@suse.com> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs@vger.kernel.org Cc: Jeff Mahoney From: Jeff Mahoney pf_queuing_worker and pf_create_prefetch_thread both try to handle thread creation failure gracefully, but assume that pthread_create doesn't modify the pthread_t when it fails. >>From the pthread_create man page: On success, pthread_create() returns 0; on error, it returns an error number, and the contents of *thread are undefined. In fact, glibc's pthread_create writes the pthread_t value before calling clone(). When we join the created threads in cleanup_inode_prefetch and the cleanup stage of pf_queuing_worker, we assume that if the pthread_t is nonzero that it's a valid thread handle and end up crashing in pthread_join. This patch zeros out the handle after pthread_create failure. Signed-off-by: Jeff Mahoney --- repair/prefetch.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/repair/prefetch.c b/repair/prefetch.c index ff50606..044fab2 100644 --- a/repair/prefetch.c +++ b/repair/prefetch.c @@ -703,6 +703,7 @@ pf_queuing_worker( if (err != 0) { do_warn(_("failed to create prefetch thread: %s\n"), strerror(err)); + args->io_threads[i] = 0; if (i == 0) { pf_start_processing(args); return NULL; @@ -816,6 +817,7 @@ pf_create_prefetch_thread( if (err != 0) { do_warn(_("failed to create prefetch thread: %s\n"), strerror(err)); + args->queuing_thread = 0; cleanup_inode_prefetch(args); } -- 2.7.1