Re: [PATCH 11/11] mempolicy: apply page table walker on queue_pages_range()

[Sasha Levin]

On 02/10/2014 04:44 PM, Naoya Horiguchi wrote:
> queue_pages_range() does page table walking in its own way now,
> so this patch rewrites it with walk_page_range().
> One difficulty was that queue_pages_range() needed to check vmas
> to determine whether we queue pages from a given vma or skip it.
> Now we have test_walk() callback in mm_walk for that purpose,
> so we can do the replacement cleanly. queue_pages_test_walk()
> depends on not only the current vma but also the previous one,
> so we use queue_pages->prev to keep it.
>
> ChangeLog v2:
> - rebase onto mmots
> - add VM_PFNMAP check on queue_pages_test_walk()
>
> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---

Hi Naoya,

I'm seeing another spew in today's -next, and it seems to be related to this patch. Here's the spew 
(with line numbers instead of kernel addresses):


[ 1411.889835] kernel BUG at mm/hugetlb.c:3580!
[ 1411.890108] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 1411.890468] Dumping ftrace buffer:
[ 1411.890468]    (ftrace buffer empty)
[ 1411.890468] Modules linked in:
[ 1411.890468] CPU: 0 PID: 2653 Comm: trinity-c285 Tainted: G        W 
3.14.0-rc3-next-20140220-sasha-00008-gab7e7ac-dirty #113
[ 1411.890468] task: ffff8801be0cb000 ti: ffff8801e471c000 task.ti: ffff8801e471c000
[ 1411.890468] RIP: 0010:[<mm/hugetlb.c:3580>]  [<mm/hugetlb.c:3580>] isolate_huge_page+0x1c/0xb0
[ 1411.890468] RSP: 0018:ffff8801e471dae8  EFLAGS: 00010246
[ 1411.890468] RAX: ffff88012b900000 RBX: ffffea0000000000 RCX: 0000000000000000
[ 1411.890468] RDX: 0000000000000000 RSI: ffff8801be0cbd00 RDI: 0000000000000000
[ 1411.890468] RBP: ffff8801e471daf8 R08: 0000000000000000 R09: 0000000000000000
[ 1411.890468] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8801e471dcf8
[ 1411.890468] R13: ffffffff87d39120 R14: ffff8801e471dbc8 R15: 00007f30b1800000
[ 1411.890468] FS:  00007f30b50bb700(0000) GS:ffff88012bc00000(0000) knlGS:0000000000000000
[ 1411.890468] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1411.890468] CR2: 0000000001609a10 CR3: 00000001e4703000 CR4: 00000000000006f0
[ 1411.890468] Stack:
[ 1411.890468]  00007f30b1000000 00007f30b0e00000 ffff8801e471db08 ffffffff812a8d71
[ 1411.890468]  ffff8801e471db78 ffffffff81298fb1 00007f30b0d00000 ffff880478a16c38
[ 1411.890468]  ffff8802291c6060 ffffffffffe00000 ffffffffffe00000 ffff8804fd7fa7d0
[ 1411.890468] Call Trace:
[ 1411.890468]  [<mm/mempolicy.c:540>] queue_pages_hugetlb+0x81/0x90
[ 1411.890468]  [<include/linux/spinlock.h:343 mm/pagewalk.c:203>] walk_hugetlb_range+0x111/0x180
[ 1411.890468]  [<mm/pagewalk.c:254>] __walk_page_range+0x25/0x40
[ 1411.890468]  [<mm/pagewalk.c:332>] walk_page_range+0xf2/0x130
[ 1411.890468]  [<mm/mempolicy.c:637>] queue_pages_range+0x6c/0x90
[ 1411.890468]  [<mm/mempolicy.c:492>] ? queue_pages_hugetlb+0x90/0x90
[ 1411.890468]  [<mm/mempolicy.c:521>] ? queue_pages_range+0x90/0x90
[ 1411.890468]  [<mm/mempolicy.c:573>] ? change_prot_numa+0x30/0x30
[ 1411.890468]  [<mm/mempolicy.c:1004>] migrate_to_node+0x77/0xc0
[ 1411.890468]  [<mm/mempolicy.c:1110>] do_migrate_pages+0x1a8/0x230
[ 1411.890468]  [<mm/mempolicy.c:1461>] SYSC_migrate_pages+0x316/0x380
[ 1411.890468]  [<include/linux/rcupdate.h:799 mm/mempolicy.c:1407>] ? SYSC_migrate_pages+0xac/0x380
[ 1411.890468]  [<kernel/sched/cputime.c:681>] ? vtime_account_user+0x91/0xa0
[ 1411.890468]  [<mm/mempolicy.c:1381>] SyS_migrate_pages+0x9/0x10
[ 1411.890468]  [<arch/x86/ia32/ia32entry.S:430>] ia32_do_call+0x13/0x13
[ 1411.890468] Code: 4c 8b 6d f8 c9 c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 54 49 89 f4 53 48 
89 fb 48 8b 07 f6 c4 40 75 13 31 f6 e8 84 48 fb ff <0f> 0b 66 90 eb fe 66 0f 1f 44 00 00 8b 4f 1c 48 
8d 77 1c 85 c9
[ 1411.890468] RIP  [<mm/hugetlb.c:3580>] isolate_huge_page+0x1c/0xb0
[ 1411.890468]  RSP <ffff8801e471dae8>


Thanks,
Sasha
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