Hi! I turned on the kernel's kobject debugging for the first time in months, to see what it would do during xfstests. During xfstests test generic/311, I got some output that looks like this: kobject: 'dm-0' (c8eee464): kobject_uevent_env kobject: 'dm-0' (c8eee464): fill_kobj_path: path = '/devices/virtual/block/dm-0' kobject: 'dm' (db0db2e0): kobject_release, parent c8eee464 (delayed) kobject: '254:0' (c42df408): kobject_uevent_env kobject: '254:0' (c42df408): fill_kobj_path: path = '/devices/virtual/bdi/254:0' kobject: '254:0' (c42df408): kobject_release, parent (null) (delayed) kobject: 'queue' (ddc489c8): kobject_uevent_env kobject: 'queue' (ddc489c8): kobject_uevent_env: filter function caused the event to drop! kobject: 'holders' (d5b7cd80): kobject_release, parent c8eee464 (delayed) kobject: 'slaves' (d5b7cf00): kobject_release, parent c8eee464 (delayed) kobject: 'dm-0' (c8eee464): kobject_uevent_env kobject: 'dm-0' (c8eee464): fill_kobj_path: path = '/devices/virtual/block/dm-0' ------------[ cut here ]------------ WARNING: CPU: 0 PID: 15689 at lib/debugobjects.c:260 debug_print_object+0x7f/0x93() ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x17 CPU: 0 PID: 15689 Comm: dmsetup Not tainted 3.11.0+ #2 Hardware name: Dell Computer Corporation Dimension 2350/07W080, BIOS A01 12/17/2002 dd459c9c dd459c9c dd459c5c c15433b8 dd459c8c c102f64d c16d7774 dd459cb8 00003d49 c16d6cc3 00000104 c130ed8f c130ed8f c5eea2b8 c173f6ac db0db328 dd459ca4 c102f6be 00000009 dd459c9c c16d7774 dd459cb8 dd459cd8 c130ed8f Call Trace: [<c15433b8>] dump_stack+0x16/0x18 [<c102f64d>] warn_slowpath_common+0x75/0x8c [<c130ed8f>] ? debug_print_object+0x7f/0x93 [<c130ed8f>] ? debug_print_object+0x7f/0x93 [<c102f6be>] warn_slowpath_fmt+0x33/0x35 [<c130ed8f>] debug_print_object+0x7f/0x93 [<c1046e3f>] ? __queue_work+0x3b0/0x3b0 [<c130f909>] debug_check_no_obj_freed+0x163/0x1a2 [<c10f8552>] kfree+0xad/0x245 [<c15495e5>] ? _raw_spin_unlock_irq+0x27/0x36 [<c140eb19>] ? __dm_destroy+0x1cd/0x221 [<c140eb19>] __dm_destroy+0x1cd/0x221 [<c140f9af>] dm_destroy+0x12/0x14 [<c14144a9>] dev_remove+0x7f/0xc4 [<c141484d>] ctl_ioctl+0x21b/0x461 [<c141442a>] ? __hash_remove+0x78/0x78 [<c1414a93>] ? ctl_ioctl+0x461/0x461 [<c1414aa4>] dm_ctl_ioctl+0x11/0x13 [<c110ee60>] do_vfs_ioctl+0x2f6/0x4cc [<c10254ed>] ? __do_page_fault+0x1b8/0x3ee [<c11076b1>] ? final_putname+0x1d/0x36 [<c1107822>] ? putname+0x23/0x32 [<c11193e8>] ? fget_light+0x22e/0x410 [<c10e8e05>] ? vm_munmap+0x3f/0x49 [<c110f075>] SyS_ioctl+0x3f/0x6a [<c138fd04>] ? perf_trace_scsi_dispatch_cmd_start+0xef/0x131 [<c154a9bb>] sysenter_do_call+0x12/0x32 [<c138fd04>] ? perf_trace_scsi_dispatch_cmd_start+0xef/0x131 ---[ end trace 270dd251caf4e8bb ]--- [failed, exit status 1] - output mismatch (see /var/lib/xfstests/results//generic/311.out.bad) --- tests/generic/311.out 2013-09-23 03:55:36.568877480 -0400 +++ /var/lib/xfstests/results//generic/311.out.bad 2013-09-24 09:03:35.115593488 -0400 @@ -1,321 +1,74 @@ QA output created by 311 +mount: wrong fs type, bad option, bad superblock on /dev/mapper/flakey-test, + missing codepage or helper program, or other error + In some cases useful info is found in syslog - try + dmesg | tail or so + Running test 1 buffered, normal suspend ... (Run 'diff -u tests/generic/311.out /var/lib/xfstests/results//generic/311.out.bad' to see the entire diff) kobject: '254:0' (c42df408): kobject_cleanup, parent (null) kobject: '254:0' (c42df408): calling ktype release kobject: '254:0': free name kobject: 'holders' (d5b7cd80): kobject_cleanup, parent c8eee464 kobject: 'holders' (d5b7cd80): auto cleanup kobject_del kobject: 'holders' (d5b7cd80): calling ktype release kobject: (d5b7cd80): dynamic_kobj_release kobject: 'holders': free name kobject: 'slaves' (d5b7cf00): kobject_cleanup, parent c8eee464 kobject: 'slaves' (d5b7cf00): auto cleanup kobject_del kobject: 'slaves' (d5b7cf00): calling ktype release kobject: (d5b7cf00): dynamic_kobj_release kobject: 'slaves': free name My FS setup (XFS + external journal) was not kind to this test, and nothing really worked correctly. However, is there anything worth chasing in this message? If nothing else, reproducibility is 100% right now. I have a newer trace, but it has only kobject-release debugging, not the full kobject debugging. The PC in use is a 32-bit x86 Pentium 4, 512 MB RAM, running slackware-current. udevd is not active, though I think the kernel's devtmpfs facility is in use (need to double-check). Thanks! Michael -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel