On Mon, 8 Nov 2010, Thomas Meyer wrote: > Am Montag, den 08.11.2010, 10:51 +0100 schrieb Thomas Gleixner: > > On Mon, 8 Nov 2010, Thomas Meyer wrote: > > > > > > > > [ 300.000697] Pid: 0, comm: kworker/0:0 Not tainted 2.6.36 #2 MS-7250/MS-7250 > > > > [ 300.000815] RIP: 0010:[<ffffffff8105faf4>] [<ffffffff8105faf4>] cascade+0x54/0x7a > > > > Can you please enable > > > > CONFIG_DEBUG_OBJECTS > > CONFIG_DEBUG_OBJECTS_FREE > > CONFIG_DEBUG_OBJECTS_TIMERS > > and set CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT to 1 > > > > That should give us more useful data. > > First results: > > WARNING: at lib/debugobjects.c:259 debug_print_object+0x5b/0x63() > Hardware name: MS-7250 > ODEBUG: free active (active state 0) object type: timer_list That means that ext4_put_super() is kfree'ing something which has an active timer embedded. That explains the crash in cascade() very well. I leave it to the ext4 experts to solve it for real :) > Modules linked in: floppy radeon ttm drm_kms_helper > Pid: 2259, comm: umount Not tainted 2.6.36 #4 > Call Trace: > [<ffffffff810577d2>] warn_slowpath_common+0x80/0x98 > [<ffffffff8105787e>] warn_slowpath_fmt+0x41/0x43 > [<ffffffff812cab46>] debug_print_object+0x5b/0x63 > [<ffffffff812cb024>] debug_check_no_obj_freed+0x94/0x1d3 > [<ffffffff817032d3>] ? _raw_spin_unlock_irq+0x1f/0x2a > [<ffffffff810e4cd7>] kfree+0x75/0xb6 > [<ffffffff81172c75>] ? ext4_put_super+0x32b/0x33a > [<ffffffff81172c75>] ext4_put_super+0x32b/0x33a > [<ffffffff810ed276>] generic_shutdown_super+0x51/0xd2 > [<ffffffff810ed319>] kill_block_super+0x22/0x3a > [<ffffffff810ecda6>] deactivate_locked_super+0x21/0x41 > [<ffffffff810ed220>] deactivate_super+0x40/0x45 > [<ffffffff811010a5>] mntput_no_expire+0xdd/0x10b > [<ffffffff8110161a>] sys_umount+0x2d2/0x2fd > [<ffffffff81705f1e>] ? do_page_fault+0x217/0x244 > [<ffffffff81022a2b>] system_call_fastpath+0x16/0x1b > > I didn't encounter a kernel crash with the DEBUG_OBJECT options enabled. That's the point of DEBUG_OBJECTs :) It detects and corrects the problem in most cases and keeps the box alive with a useful error report. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
