Hi guys, I hit following warning with 3.9-rc5, during unmount (the device was mounted via loop device, in case it matters).
Jongman. [ 3600.583547] INFO: task umount:29671 blocked for more than 120 seconds. [ 3600.583552] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 3600.583555] umount D 0000000000000001 0 29671 29632 0x00000000 [ 3600.583561] ffff88011ecb5c98 0000000000000086 ffff880130ccade0 0000000000013e40 [ 3600.583566] ffff88011ecb5fd8 ffff88011ecb4010 0000000000013e40 0000000000013e40 [ 3600.583571] ffff88011ecb5fd8 0000000000013e40 ffff880132518000 ffff880130ccade0 [ 3600.583575] Call Trace: [ 3600.583583] [<ffffffff816fb669>] schedule+0x29/0x70 [ 3600.583589] [<ffffffff816fb98e>] schedule_preempt_disabled+0xe/0x10 [ 3600.583593] [<ffffffff816fa0af>] __mutex_lock_slowpath+0xdf/0x160 [ 3600.583598] [<ffffffff811e433e>] ? release_sysfs_dirent+0x7e/0x100 [ 3600.583603] [<ffffffff816f9fab>] mutex_lock+0x2b/0x50 [ 3600.583607] [<ffffffff8149a8aa>] loop_clr_fd+0x24a/0x2e0 [ 3600.583612] [<ffffffff816fce3e>] ? _raw_spin_lock+0xe/0x20 [ 3600.583617] [<ffffffff8149a9b8>] lo_release+0x78/0x90 [ 3600.583622] [<ffffffff811a94e4>] __blkdev_put+0x194/0x1d0 [ 3600.583628] [<ffffffff811a957d>] blkdev_put+0x5d/0x160 [ 3600.583633] [<ffffffff811719bd>] kill_block_super+0x4d/0x80 [ 3600.583638] [<ffffffff81171f35>] deactivate_locked_super+0x45/0x70 [ 3600.583643] [<ffffffff81172dda>] deactivate_super+0x4a/0x70 [ 3600.583648] [<ffffffff8118e538>] mntput_no_expire+0xf8/0x150 [ 3600.583653] [<ffffffff8118eded>] sys_umount+0xcd/0x3e0 [ 3600.583659] [<ffffffff817058d9>] system_call_fastpath+0x16/0x1b [ 3600.583663] INFO: task blkid:29673 blocked for more than 120 seconds. [ 3600.583665] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 3600.583667] blkid D ffffffff81807f20 0 29673 1 0x00000000 [ 3600.583672] ffff88011338fa88 0000000000000082 ffff880130ccc4d0 0000000000013e40 [ 3600.583677] ffff88011338ffd8 ffff88011338e010 0000000000013e40 0000000000013e40 [ 3600.583681] ffff88011338ffd8 0000000000013e40 ffff880132b416f0 ffff880130ccc4d0 [ 3600.583686] Call Trace: [ 3600.583691] [<ffffffff816fb669>] schedule+0x29/0x70 [ 3600.583695] [<ffffffff816fb98e>] schedule_preempt_disabled+0xe/0x10 [ 3600.583700] [<ffffffff816fa0af>] __mutex_lock_slowpath+0xdf/0x160 [ 3600.583704] [<ffffffff816f9fab>] mutex_lock+0x2b/0x50 [ 3600.583709] [<ffffffff811a9723>] __blkdev_get+0x73/0x480 [ 3600.583714] [<ffffffff811a9e90>] ? blkdev_get+0x360/0x360 [ 3600.583719] [<ffffffff811a9b81>] blkdev_get+0x51/0x360 [ 3600.583724] [<ffffffff816fce3e>] ? _raw_spin_lock+0xe/0x20 [ 3600.583729] [<ffffffff811a9e90>] ? blkdev_get+0x360/0x360 [ 3600.583734] [<ffffffff811a9ef2>] blkdev_open+0x62/0x80 [ 3600.583739] [<ffffffff8116d82e>] do_dentry_open+0x23e/0x2c0 [ 3600.583743] [<ffffffff8116d9c5>] finish_open+0x35/0x50 [ 3600.583748] [<ffffffff8117c7b6>] do_last+0x696/0xe50 [ 3600.583752] [<ffffffff81166984>] ? kmem_cache_alloc_trace+0xc4/0x120 [ 3600.583757] [<ffffffff8117f7c8>] path_openat+0xb8/0x490 [ 3600.583762] [<ffffffff8117fcd9>] do_filp_open+0x49/0xa0 [ 3600.583767] [<ffffffff816fce3e>] ? _raw_spin_lock+0xe/0x20 [ 3600.583772] [<ffffffff8118c4e5>] ? __alloc_fd+0xb5/0x160 [ 3600.583777] [<ffffffff8116d498>] do_sys_open+0x108/0x1f0 [ 3600.583781] [<ffffffff8116d5c1>] sys_open+0x21/0x30 [ 3600.583786] [<ffffffff817058d9>] system_call_fastpath+0x16/0x1bN�����r��y����b�X��ǧv�^�){.n�+����{����zX����ܨ}���Ơz�&j:+v�������zZ+��+zf���h���~����i���z��w���?�����&�)ߢf��^jǫy�m��@A�a��� 0��h���i