On Tue, 2014-03-11 at 18:06 +0000, Mel Gorman wrote: > On Tue, Mar 11, 2014 at 01:33:00PM -0400, Sasha Levin wrote: > > Okay. So just this patch on top of the latest -next shows the following issues: > > > > 1. BUG in task_numa_work: > > > > [ 439.417171] BUG: unable to handle kernel paging request at ffff880e17530c00 > > [ 439.418216] IP: [<ffffffff81299385>] vmacache_find+0x75/0xa0 > > [ 439.419073] PGD 8904067 PUD 1028fcb067 PMD 1028f10067 PTE 8000000e17530060 > > [ 439.420340] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > > [ 439.420340] Dumping ftrace buffer: > > [ 439.420340] (ftrace buffer empty) > > [ 439.420340] Modules linked in: > > [ 439.420340] CPU: 12 PID: 9937 Comm: trinity-c212 Tainted: G W 3.14.0-rc5-next-20140307-sasha-00009-g3b24300-dirty #137 > > [ 439.420340] task: ffff880e1a45b000 ti: ffff880e1a490000 task.ti: ffff880e1a490000 > > [ 439.420340] RIP: 0010:[<ffffffff81299385>] [<ffffffff81299385>] vmacache_find+0x75/0xa0 > > [ 439.420340] RSP: 0018:ffff880e1a491e68 EFLAGS: 00010286 > > [ 439.420340] RAX: ffff880e17530c00 RBX: 0000000000000000 RCX: 0000000000000001 > > [ 439.420340] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff880e1a45b000 > > [ 439.420340] RBP: ffff880e1a491e68 R08: 0000000000000000 R09: 0000000000000000 > > [ 439.420340] R10: 0000000000000001 R11: 0000000000000000 R12: ffff880e1ab75000 > > [ 439.420340] R13: ffff880e1ab75000 R14: 0000000000010000 R15: 0000000000000000 > > [ 439.420340] FS: 00007f3458c05700(0000) GS:ffff880d2b800000(0000) knlGS:0000000000000000 > > [ 439.420340] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > > [ 439.420340] CR2: ffff880e17530c00 CR3: 0000000e1a472000 CR4: 00000000000006a0 > > [ 439.420340] Stack: > > [ 439.420340] ffff880e1a491e98 ffffffff812a7610 ffffffff8118de40 0000000000000117 > > [ 439.420340] 00000001000036da ffff880e1a45b000 ffff880e1a491ef8 ffffffff8118de4b > > [ 439.420340] ffff880e1a491ec8 ffffffff81269575 ffff880e1ab750a8 ffff880e1a45b000 > > [ 439.420340] Call Trace: > > [ 439.420340] [<ffffffff812a7610>] find_vma+0x20/0x90 > > [ 439.420340] [<ffffffff8118de40>] ? task_numa_work+0x130/0x360 > > [ 439.420340] [<ffffffff8118de4b>] task_numa_work+0x13b/0x360 > > [ 439.420340] [<ffffffff81269575>] ? context_tracking_user_exit+0x195/0x1d0 > > [ 439.420340] [<ffffffff8116c5be>] task_work_run+0xae/0xf0 > > [ 439.420340] [<ffffffff8106ffbe>] do_notify_resume+0x8e/0xe0 > > [ 439.420340] [<ffffffff844b17a2>] int_signal+0x12/0x17 > > [ 439.420340] Code: 42 10 00 00 00 00 48 c7 42 18 00 00 00 00 eb 38 66 0f 1f 44 00 00 31 d2 48 89 c7 48 63 ca 48 8b 84 cf b8 07 00 00 48 85 c0 74 0b <48> 39 30 77 06 48 3b 70 08 72 12 ff c2 83 fa 04 75 de 66 0f 1f > > [ 439.420340] RIP [<ffffffff81299385>] vmacache_find+0x75/0xa0 > > [ 439.420340] RSP <ffff880e1a491e68> > > [ 439.420340] CR2: ffff880e17530c00 > > > > Ok, this does not look related. It looks like damage from the VMA caching > patches, possibly a use-after free. I'm skeptical that it's related to > automatic NUMA balancing as such based on the second trace you posted. Indeed, this issue is separate. It was reported a few days ago by Fengguang: http://lkml.org/lkml/2014/3/9/201 Apparently this has only been seen in DEBUG_PAGEALLOC + trinity scenarios, just like in Sasha's trace. I'm suspecting some invalidation is missing (not sure what DEBUG_PAGEALLOC enables differently in this aspect), as when we do the vmacache_find() the vma is bogus which triggers the paging request error. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>