Hi, On 01/12/2018 11:43 AM, Shichangkuo wrote: > Hi all, > Now we are testing ocfs2 with 4.14 kernel, and we finding a deadlock with > umount and ocfs2 workqueue triggered by ocfs2rec thread. The stack as follows: > journal recovery work: > [<ffffffff8a8c0694>] call_rwsem_down_read_failed+0x14/0x30 > [<ffffffffc0d5d652>] ocfs2_finish_quota_recovery+0x62/0x450 [ocfs2] > [<ffffffffc0d21221>] ocfs2_complete_recovery+0xc1/0x440 [ocfs2] > [<ffffffff8a09a1f0>] process_one_work+0x130/0x350 > [<ffffffff8a09a946>] worker_thread+0x46/0x3b0 > [<ffffffff8a0a0e51>] kthread+0x101/0x140 > [<ffffffff8aa002ff>] ret_from_fork+0x1f/0x30 > [<ffffffffffffffff>] 0xffffffffffffffff > > /bin/umount: > [<ffffffff8a099b24>] flush_workqueue+0x104/0x3e0 > [<ffffffffc0cf18db>] ocfs2_truncate_log_shutdown+0x3b/0xc0 [ocfs2] > [<ffffffffc0d4fd6c>] ocfs2_dismount_volume+0x8c/0x3d0 [ocfs2] > [<ffffffffc0d500e1>] ocfs2_put_super+0x31/0xa0 [ocfs2] > [<ffffffff8a2445bd>] generic_shutdown_super+0x6d/0x120 > [<ffffffff8a24469d>] kill_block_super+0x2d/0x60 > [<ffffffff8a244e71>] deactivate_locked_super+0x51/0x90 > [<ffffffff8a263a1b>] cleanup_mnt+0x3b/0x70 > [<ffffffff8a09e9c6>] task_work_run+0x86/0xa0 > [<ffffffff8a003d70>] exit_to_usermode_loop+0x6d/0xa9 > [<ffffffff8a003a2d>] do_syscall_64+0x11d/0x130 > [<ffffffff8aa00113>] entry_SYSCALL64_slow_path+0x25/0x25 > [<ffffffffffffffff>] 0xffffffffffffffff > > Function ocfs2_finish_quota_recovery try to get sb->s_umount, which was > already locked by umount thread, then get a deadlock.
Good catch, thanks for reporting. Is it reproducible? Can you please share the steps for reproducing this issue? > This issue was introduced by c3b004460d77bf3f980d877be539016f2df4df12 and > 5f530de63cfc6ca8571cbdf58af63fb166cc6517. > I think we cannot use :: s_umount, but the mutex ::dqonoff_mutex was already > removed. > Shall we add a new mutex? @Jan, I don't look into the code yet, could you help me understand why we need to get sb->s_umount in ocfs2_finish_quota_recovery? Is it because that the quota recovery process will start at umounting? or some where else? Thanks, Eric _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel