On 03/11/2014 02:06 PM, 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.
It's a bit weird because right after applying the patch I've hit this trace
twice while
never seeing it previously.
But it's very possible since there are quite a lot of different mm issues
around right now.
What does addr2line -e vmlinux ffffffff81299385 say? I want to be sure
it looks like a vma dereference without risking making a mistake
decoding it.
mm/vmacache.c:75
Or:
if (vma && vma->vm_start <= addr && vma->vm_end > addr)
1. Does this bug trigger even if automatic NUMA balancing is disabled?
(assuming we're talking about kernel BUG at mm/mmap.c:439!)
Yes, same result with numa_balancing=disable.
2. Does this bug trigger if DEBUG_PAGEALLOC is disabled? If it's a
use-after free then the bug would still be there.
Still there.
3. Can you test with the following patches reverted please?
e15d25d9c827b4346a36a3a78dd566d5ad353402
mm-per-thread-vma-caching-fix-fix
e440e20dc76803cdab616b4756c201d5c72857f2 mm-per-thread-vma-caching-fix
0d9ad4220e6d73f63a9eeeaac031b92838f75bb3 mm: per-thread vma caching
The last patch will not revert cleanly (least it didn't for me) but it
was just a case of git rm the two affected files, remove any include of
vmacache.h and commit the rest.
Don't see the issues I've reported before now.
Thanks,
Sasha
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