On 2011.11.23 at 10:06 -0600, Christoph Lameter wrote: > On Wed, 23 Nov 2011, Markus Trippelsdorf wrote: > > > > FIX idr_layer_cache: Marking all objects used > > > > Yesterday I couldn't reproduce the issue at all. But today I've hit > > exactly the same spot again. (CCing the drm list) > > Well this is looks like write after free. > > > ============================================================================= > > BUG idr_layer_cache: Poison overwritten > > ----------------------------------------------------------------------------- > > Object ffff8802156487c0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk > > Object ffff8802156487d0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk > > Object ffff8802156487e0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk > > Object ffff8802156487f0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk > > Object ffff880215648800: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b ....kkkkkkkkkkkk > > Object ffff880215648810: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk > > And its an integer sized write of 0. If you look at the struct definition > and lookup the offset you should be able to locate the field that > was modified. Here are two more BUGs that seem to point to the same bug: 1) ... Nov 21 18:30:30 x4 kernel: [drm] radeon: irq initialized. Nov 21 18:30:30 x4 kernel: [drm] GART: num cpu pages 131072, num gpu pages 131072 Nov 21 18:30:30 x4 kernel: [drm] Loading RS780 Microcode Nov 21 18:30:30 x4 kernel: [drm] PCIE GART of 512M enabled (table at 0x00000000C0040000). Nov 21 18:30:30 x4 kernel: radeon 0000:01:05.0: WB enabled Nov 21 18:30:30 x4 kernel: ============================================================================= Nov 21 18:30:30 x4 kernel: BUG task_xstate: Not a valid slab page Nov 21 18:30:30 x4 kernel: ----------------------------------------------------------------------------- Nov 21 18:30:30 x4 kernel: Nov 21 18:30:30 x4 kernel: INFO: Slab 0xffffea0000044300 objects=32767 used=65535 fp=0x (null) flags=0x0401 Nov 21 18:30:30 x4 kernel: Pid: 9, comm: ksoftirqd/1 Not tainted 3.2.0-rc2-00274-g6fe4c6d-dirty #75 Nov 21 18:30:30 x4 kernel: Call Trace: Nov 21 18:30:30 x4 kernel: [<ffffffff81101c1d>] slab_err+0x7d/0x90 Nov 21 18:30:30 x4 kernel: [<ffffffff8103e29f>] ? dump_trace+0x16f/0x2e0 Nov 21 18:30:30 x4 kernel: [<ffffffff81044764>] ? free_thread_xstate+0x24/0x40 Nov 21 18:30:30 x4 kernel: [<ffffffff81044764>] ? free_thread_xstate+0x24/0x40 Nov 21 18:30:30 x4 kernel: [<ffffffff81102566>] check_slab+0x96/0xc0 Nov 21 18:30:30 x4 kernel: [<ffffffff814c5c29>] free_debug_processing+0x34/0x19c Nov 21 18:30:30 x4 kernel: [<ffffffff81101d9a>] ? set_track+0x5a/0x190 Nov 21 18:30:30 x4 kernel: [<ffffffff8110cf2b>] ? sys_open+0x1b/0x20 Nov 21 18:30:30 x4 kernel: [<ffffffff814c5e55>] __slab_free+0x33/0x2d0 Nov 21 18:30:30 x4 kernel: [<ffffffff8110cf2b>] ? sys_open+0x1b/0x20 Nov 21 18:30:30 x4 kernel: [<ffffffff81105134>] kmem_cache_free+0x104/0x120 Nov 21 18:30:30 x4 kernel: [<ffffffff81044764>] free_thread_xstate+0x24/0x40 Nov 21 18:30:30 x4 kernel: [<ffffffff81044794>] free_thread_info+0x14/0x30 Nov 21 18:30:30 x4 kernel: [<ffffffff8106a4ff>] free_task+0x2f/0x50 Nov 21 18:30:30 x4 kernel: [<ffffffff8106a5d0>] __put_task_struct+0xb0/0x110 Nov 21 18:30:30 x4 kernel: [<ffffffff8106eb4b>] delayed_put_task_struct+0x3b/0xa0 Nov 21 18:30:30 x4 kernel: [<ffffffff810aa01a>] __rcu_process_callbacks+0x12a/0x350 Nov 21 18:30:30 x4 kernel: [<ffffffff810aa2a2>] rcu_process_callbacks+0x62/0x140 Nov 21 18:30:30 x4 kernel: [<ffffffff81072e18>] __do_softirq+0xa8/0x200 Nov 21 18:30:30 x4 kernel: [<ffffffff81073077>] run_ksoftirqd+0x107/0x210 Nov 21 18:30:30 x4 kernel: [<ffffffff81072f70>] ? __do_softirq+0x200/0x200 Nov 21 18:30:30 x4 kernel: [<ffffffff8108bb87>] kthread+0x87/0x90 Nov 21 18:30:30 x4 kernel: [<ffffffff814cdcf4>] kernel_thread_helper+0x4/0x10 Nov 21 18:30:30 x4 kernel: [<ffffffff8108bb00>] ? kthread_flush_work_fn+0x10/0x10 Nov 21 18:30:30 x4 kernel: [<ffffffff814cdcf0>] ? gs_change+0xb/0xb Nov 21 18:30:30 x4 kernel: FIX task_xstate: Object at 0xffffffff8110cf2b not freed Nov 21 18:30:30 x4 kernel: [drm] ring test succeeded in 1 usecs Nov 21 18:30:30 x4 kernel: [drm] radeon: ib pool ready. Nov 21 18:30:30 x4 kernel: [drm] ib test succeeded in 0 usecs Nov 21 18:30:30 x4 kernel: [drm] Radeon Display Connectors Nov 21 18:30:30 x4 kernel: [drm] Connector 0 2) ... Nov 21 17:04:38 x4 kernel: fbcon: radeondrmfb (fb0) is primary device Nov 21 17:04:38 x4 kernel: Console: switching to colour frame buffer device 131x105 Nov 21 17:04:38 x4 kernel: fb0: radeondrmfb frame buffer device Nov 21 17:04:38 x4 kernel: drm: registered panic notifier Nov 21 17:04:38 x4 kernel: [drm] Initialized radeon 2.11.0 20080528 for 0000:01:05.0 on minor 0 Nov 21 17:04:38 x4 kernel: loop: module loaded Nov 21 17:04:38 x4 kernel: ahci 0000:00:11.0: version 3.0 Nov 21 17:04:38 x4 kernel: ahci 0000:00:11.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22 Nov 21 17:04:38 x4 kernel: ahci 0000:00:11.0: AHCI 0001.0100 32 slots 6 ports 3 Gbps 0x3f impl SATA mode Nov 21 17:04:38 x4 kernel: ahci 0000:00:11.0: flags: 64bit ncq sntf ilck pm led clo pmp pio slum part ccc Nov 21 17:04:38 x4 kernel: scsi0 : ahci Nov 21 17:04:38 x4 kernel: scsi1 : ahci Nov 21 17:04:38 x4 kernel: ============================================================================= Nov 21 17:04:38 x4 kernel: BUG task_struct: Poison overwritten Nov 21 17:04:38 x4 kernel: ----------------------------------------------------------------------------- Nov 21 17:04:38 x4 kernel: Nov 21 17:04:38 x4 kernel: INFO: 0xffff880215c43800-0xffff880215c43803. First byte 0x0 instead of 0x6b Nov 21 17:04:38 x4 kernel: INFO: Allocated in copy_process+0xc4/0xf60 age=168 cpu=1 pid=5 Nov 21 17:04:38 x4 kernel: __slab_alloc.constprop.70+0x1a4/0x1e0 Nov 21 17:04:38 x4 kernel: kmem_cache_alloc+0x126/0x160 Nov 21 17:04:38 x4 kernel: copy_process+0xc4/0xf60 Nov 21 17:04:38 x4 kernel: do_fork+0x100/0x2b0 Nov 21 17:04:38 x4 kernel: kernel_thread+0x6c/0x70 Nov 21 17:04:38 x4 kernel: __call_usermodehelper+0x31/0xa0 Nov 21 17:04:38 x4 kernel: process_one_work+0x11a/0x430 Nov 21 17:04:38 x4 kernel: worker_thread+0x126/0x2d0 Nov 21 17:04:38 x4 kernel: kthread+0x87/0x90 Nov 21 17:04:38 x4 kernel: kernel_thread_helper+0x4/0x10 Nov 21 17:04:38 x4 kernel: INFO: Freed in free_task+0x3e/0x50 age=156 cpu=2 pid=13 Nov 21 17:04:38 x4 kernel: __slab_free+0x33/0x2d0 Nov 21 17:04:38 x4 kernel: kmem_cache_free+0x104/0x120 Nov 21 17:04:38 x4 kernel: free_task+0x3e/0x50 Nov 21 17:04:38 x4 kernel: __put_task_struct+0xb0/0x110 Nov 21 17:04:38 x4 kernel: delayed_put_task_struct+0x3b/0xa0 Nov 21 17:04:38 x4 kernel: __rcu_process_callbacks+0x12a/0x350 Nov 21 17:04:38 x4 kernel: rcu_process_callbacks+0x62/0x140 Nov 21 17:04:38 x4 kernel: __do_softirq+0xa8/0x200 Nov 21 17:04:38 x4 kernel: run_ksoftirqd+0x107/0x210 Nov 21 17:04:38 x4 kernel: kthread+0x87/0x90 Nov 21 17:04:38 x4 kernel: kernel_thread_helper+0x4/0x10 Nov 21 17:04:38 x4 kernel: INFO: Slab 0xffffea0008571000 objects=17 used=17 fp=0x (null) flags=0x4000000000004080 Nov 21 17:04:38 x4 kernel: INFO: Object 0xffff880215c432c0 @offset=12992 fp=0xffff880215c41d00 Nov 21 17:04:38 x4 kernel: Nov 21 17:04:38 x4 kernel: Bytes b4 ffff880215c432b0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ Nov 21 17:04:38 x4 kernel: Object ffff880215c432c0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk ... Nov 21 17:04:38 x4 kernel: Object ffff880215c437f0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43800: 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b ....kkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43810: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43820: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43830: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43840: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43850: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43860: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43870: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43880: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c43890: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Nov 21 17:04:38 x4 kernel: Object ffff880215c438a0: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk. Nov 21 17:04:38 x4 kernel: Redzone ffff880215c438b0: bb bb bb bb bb bb bb bb ........ Nov 21 17:04:38 x4 kernel: Padding ffff880215c439f0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ Nov 21 17:04:38 x4 kernel: Pid: 5, comm: kworker/u:0 Not tainted 3.2.0-rc2-00274-g6fe4c6d #72 Nov 21 17:04:38 x4 kernel: Call Trace: Nov 21 17:04:38 x4 kernel: [<ffffffff81101ca8>] ? print_section+0x38/0x40 Nov 21 17:04:38 x4 kernel: [<ffffffff811021a3>] print_trailer+0xe3/0x150 Nov 21 17:04:38 x4 kernel: [<ffffffff811023a0>] check_bytes_and_report+0xe0/0x100 Nov 21 17:04:38 x4 kernel: [<ffffffff81103196>] check_object+0x1c6/0x240 Nov 21 17:04:38 x4 kernel: [<ffffffff8106b034>] ? copy_process+0xc4/0xf60 Nov 21 17:04:38 x4 kernel: [<ffffffff814c5bb3>] alloc_debug_processing+0x62/0xe4 Nov 21 17:04:38 x4 kernel: [<ffffffff814c6461>] __slab_alloc.constprop.70+0x1a4/0x1e0 Nov 21 17:04:38 x4 kernel: [<ffffffff8106b034>] ? copy_process+0xc4/0xf60 Nov 21 17:04:38 x4 kernel: [<ffffffff814ca12a>] ? schedule+0x3a/0x50 Nov 21 17:04:38 x4 kernel: [<ffffffff81104d66>] kmem_cache_alloc+0x126/0x160 Nov 21 17:04:38 x4 kernel: [<ffffffff8106b034>] ? copy_process+0xc4/0xf60 Nov 21 17:04:38 x4 kernel: [<ffffffff81065f18>] ? enqueue_task_fair+0xf8/0x140 Nov 21 17:04:38 x4 kernel: [<ffffffff8106b034>] copy_process+0xc4/0xf60 Nov 21 17:04:38 x4 kernel: [<ffffffff8106c000>] do_fork+0x100/0x2b0 Nov 21 17:04:38 x4 kernel: [<ffffffff810920fd>] ? sched_clock_local+0x1d/0x90 Nov 21 17:04:38 x4 kernel: [<ffffffff81044dec>] kernel_thread+0x6c/0x70 Nov 21 17:04:38 x4 kernel: [<ffffffff81084430>] ? proc_cap_handler+0x180/0x180 Nov 21 17:04:38 x4 kernel: [<ffffffff814cdd30>] ? gs_change+0xb/0xb Nov 21 17:04:38 x4 kernel: [<ffffffff810845a1>] __call_usermodehelper+0x31/0xa0 Nov 21 17:04:38 x4 kernel: [<ffffffff810869ba>] process_one_work+0x11a/0x430 Nov 21 17:04:38 x4 kernel: [<ffffffff81084570>] ? call_usermodehelper_freeinfo+0x30/0x30 Nov 21 17:04:38 x4 kernel: [<ffffffff81087026>] worker_thread+0x126/0x2d0 Nov 21 17:04:38 x4 kernel: [<ffffffff81086f00>] ? rescuer_thread+0x1f0/0x1f0 Nov 21 17:04:38 x4 kernel: [<ffffffff8108bb87>] kthread+0x87/0x90 Nov 21 17:04:38 x4 kernel: [<ffffffff814cdd34>] kernel_thread_helper+0x4/0x10 Nov 21 17:04:38 x4 kernel: [<ffffffff8108bb00>] ? kthread_flush_work_fn+0x10/0x10 Nov 21 17:04:38 x4 kernel: [<ffffffff814cdd30>] ? gs_change+0xb/0xb Nov 21 17:04:38 x4 kernel: FIX task_struct: Restoring 0xffff880215c43800-0xffff880215c43803=0x6b Nov 21 17:04:38 x4 kernel: Nov 21 17:04:38 x4 kernel: FIX task_struct: Marking all objects used -- Markus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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