From: Yiwen Jiang Date: Tue, 21 Jan 2014 23:48:39 +0000 (-0800) Subject: ocfs2: fix NULL pointer dereference when dismount and ocfs2rec simultaneously X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=75f82eaa502c;p=openwrt%2Fstaging%2Fblogic.git ocfs2: fix NULL pointer dereference when dismount and ocfs2rec simultaneously 2 nodes cluster, say Node A and Node B, mount the same ocfs2 volume, and create a file 1. Node A Node B open 1, get open lock rm 1, and then add 1 to orphan_dir storage link down, o2hb_write_timeout ->o2quo_disk_timeout ->emergency_restart at the moment, Node B dismount and do ocfs2rec simultaneously 1) ocfs2_dismount_volume ->ocfs2_recovery_exit ->wait_event(osb->recovery_event) ->flush_workqueue(ocfs2_wq) 2) ocfs2rec ->queue_work(&journal->j_recovery_work) ->ocfs2_recover_orphans ->ocfs2_commit_truncate ->queue_delayed_work(&osb->osb_truncate_log_wq) In ocfs2_recovery_exit, it flushes workqueue and then releases system inodes. When doing ocfs2rec, it will call ocfs2_flush_truncate_log which will try to get sys_root_inode, and NULL pointer dereference occurs. Signed-off-by: Yiwen Jiang Signed-off-by: joyce Signed-off-by: Joseph Qi Cc: Joel Becker Cc: Mark Fasheh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c index 5445d72eb8e5..49d84f80f36c 100644 --- a/fs/ocfs2/super.c +++ b/fs/ocfs2/super.c @@ -1945,11 +1945,15 @@ static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err) ocfs2_shutdown_local_alloc(osb); - ocfs2_truncate_log_shutdown(osb); - /* This will disable recovery and flush any recovery work. */ ocfs2_recovery_exit(osb); + /* + * During dismount, when it recovers another node it will call + * ocfs2_recover_orphans and queue delayed work osb_truncate_log_wq. + */ + ocfs2_truncate_log_shutdown(osb); + ocfs2_journal_shutdown(osb); ocfs2_sync_blockdev(sb);