Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933324AbbHXJSm (ORCPT ); Mon, 24 Aug 2015 05:18:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:58314 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932799AbbHXJKM (ORCPT ); Mon, 24 Aug 2015 05:10:12 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Joseph Qi , Mark Fasheh , Joel Becker , Andrew Morton , Linus Torvalds , Jiri Slaby Subject: [PATCH 3.12 55/82] ocfs2: fix BUG in ocfs2_downconvert_thread_do_work() Date: Mon, 24 Aug 2015 11:09:15 +0200 Message-Id: X-Mailer: git-send-email 2.5.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2205 Lines: 57 From: Joseph Qi 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 209f7512d007980fd111a74a064d70a3656079cf upstream. The "BUG_ON(list_empty(&osb->blocked_lock_list))" in ocfs2_downconvert_thread_do_work can be triggered in the following case: ocfs2dc has firstly saved osb->blocked_lock_count to local varibale processed, and then processes the dentry lockres. During the dentry put, it calls iput and then deletes rw, inode and open lockres from blocked list in ocfs2_mark_lockres_freeing. And this causes the variable `processed' to not reflect the number of blocked lockres to be processed, which triggers the BUG. Signed-off-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- fs/ocfs2/dlmglue.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c index 3988d0aeb72c..416a2ab68ac1 100644 --- a/fs/ocfs2/dlmglue.c +++ b/fs/ocfs2/dlmglue.c @@ -4009,9 +4009,13 @@ static void ocfs2_downconvert_thread_do_work(struct ocfs2_super *osb) osb->dc_work_sequence = osb->dc_wake_sequence; processed = osb->blocked_lock_count; - while (processed) { - BUG_ON(list_empty(&osb->blocked_lock_list)); - + /* + * blocked lock processing in this loop might call iput which can + * remove items off osb->blocked_lock_list. Downconvert up to + * 'processed' number of locks, but stop short if we had some + * removed in ocfs2_mark_lockres_freeing when downconverting. + */ + while (processed && !list_empty(&osb->blocked_lock_list)) { lockres = list_entry(osb->blocked_lock_list.next, struct ocfs2_lock_res, l_blocked_list); list_del_init(&lockres->l_blocked_list); -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/