Re: 3.15-rc8 mm/filemap.c:202 BUG

[Sasha Levin]

On 06/03/2014 07:11 PM, Hugh Dickins wrote:
> On Tue, 3 Jun 2014, Konstantin Khlebnikov wrote:
>> > On Tue, Jun 3, 2014 at 8:21 AM, Dave Jones <davej@xxxxxxxxxx> wrote:
>>> > > I'm still seeing this one from time to time, though it takes me quite a while to hit it,
>>> > > despite my attempts at trying to narrow down the set of syscalls that cause it.
>>> > >
>>> > > kernel BUG at mm/filemap.c:202!
>>> > > invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
>>> > > CPU: 3 PID: 3013 Comm: trinity-c361 Not tainted 3.15.0-rc8+ #225
>>> > > task: ffff88006c610000 ti: ffff880055960000 task.ti: ffff880055960000
>>> > > RIP: 0010:[<ffffffffac158e28>]  [<ffffffffac158e28>] __delete_from_page_cache+0x318/0x360
>>> > > RSP: 0018:ffff880055963b90  EFLAGS: 00010046
>>> > > RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffff880146f68388
>>> > > RDX: 000000000000022a RSI: ffffffffaca8db38 RDI: ffffffffaca62b17
>>> > > RBP: ffff880055963be0 R08: 0000000000000002 R09: ffff88000613d530
>>> > > R10: ffff880055963ba8 R11: ffff880007f49a40 R12: ffffea0006795880
>>> > > R13: ffff880143232ad0 R14: 0000000000000000 R15: ffff880143232ad8
>>> > > FS:  00007f1e40673700(0000) GS:ffff88024d180000(0000) knlGS:0000000000000000
>>> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> > > CR2: 00007f1e404e6000 CR3: 00000000603eb000 CR4: 00000000001407e0
>>> > > DR0: 0000000001bb1000 DR1: 0000000002537000 DR2: 00000000016a5000
>>> > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
>>> > > Stack:
>>> > >  ffff880143232ae8 0000000000000000 ffff88000613d530 ffff88000613d568
>>> > >  0000000008828259 ffffea0006795880 ffff880143232ae8 0000000000000000
>>> > >  0000000000000002 0000000000000002 ffff880055963c08 ffffffffac158eae
>>> > > Call Trace:
>>> > >  [<ffffffffac158eae>] delete_from_page_cache+0x3e/0x70
>>> > >  [<ffffffffac16921b>] truncate_inode_page+0x5b/0x90
>>> > >  [<ffffffffac174493>] shmem_undo_range+0x363/0x790
>>> > >  [<ffffffffac1748d4>] shmem_truncate_range+0x14/0x30
>>> > >  [<ffffffffac174bcf>] shmem_fallocate+0x9f/0x340
>>> > >  [<ffffffffac324d40>] ? timerqueue_add+0x60/0xb0
>>> > >  [<ffffffffac1c5ff6>] do_fallocate+0x116/0x1a0
>>> > >  [<ffffffffac182260>] SyS_madvise+0x3c0/0x870
>>> > >  [<ffffffffac346b33>] ? __this_cpu_preempt_check+0x13/0x20
>>> > >  [<ffffffffac74c41f>] tracesys+0xdd/0xe2
>>> > > Code: ff ff 01 41 f6 c6 01 48 8b 45 c8 75 16 4c 89 30 e9 70 fe ff ff 66 0f 1f 44 00 00 0f 0b 66 0f 1f 44 00 00 0f 0b 66 0f 1f 44 00 00 <0f> 0b 66 0f 1f 44 00 00  41 54 9d e8 78 9e fd ff e9 8c fe ff ff
>>> > > RIP  [<ffffffffac158e28>] __delete_from_page_cache+0x318/0x360
>>> > >
>>> > > There was also another variant of the same BUG with a slighty different stack trace.
>>> > >
>>> > > kernel BUG at mm/filemap.c:202!
>>> > > invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
>>> > > CPU: 2 PID: 6928 Comm: trinity-c45 Not tainted 3.15.0-rc5+ #208
>>> > > task: ffff88023669d0a0 ti: ffff880186146000 task.ti: ffff880186146000
>>> > > RIP: 0010:[<ffffffff8415ba05>]  [<ffffffff8415ba05>] __delete_from_page_cache+0x315/0x320
>>> > > RSP: 0018:ffff880186147b18  EFLAGS: 00010046
>>> > > RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000002
>>> > > RDX: 000000000000012a RSI: ffffffff84a9a83c RDI: ffffffff84a6e0c0
>>> > > RBP: ffff880186147b68 R08: 0000000000000002 R09: ffff88002669e668
>>> > > R10: ffff880186147b30 R11: 0000000000000000 R12: ffffea0008b067c0
>>> > > R13: ffff880025355670 R14: 0000000000000000 R15: ffff880025355678
>>> > > FS:  00007fc10026f740(0000) GS:ffff880244400000(0000) knlGS:0000000000000000
>>> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> > > CR2: 00002ab350f5c004 CR3: 000000018566c000 CR4: 00000000001407e0
>>> > > DR0: 0000000001989000 DR1: 0000000000944000 DR2: 0000000002494000
>>> > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
>>> > > Stack:
>>> > >  ffff880025355688 ffff8800253556a0 ffff88002669e668 ffff88002669e6a0
>>> > >  000000008ea099ef ffffea0008b067c0 ffff880025355688 0000000000000000
>>> > >  0000000000000000 0000000000000002 ffff880186147b90 ffffffff8415ba4d
>>> > > Call Trace:
>>> > >  [<ffffffff8415ba4d>] delete_from_page_cache+0x3d/0x70
>>> > >  [<ffffffff8416b0ab>] truncate_inode_page+0x5b/0x90
>>> > >  [<ffffffff84175f0b>] shmem_undo_range+0x30b/0x780
>>> > >  [<ffffffff84176394>] shmem_truncate_range+0x14/0x30
>>> > >  [<ffffffff8417647d>] shmem_evict_inode+0xcd/0x150
>>> > >  [<ffffffff841e4b17>] evict+0xa7/0x170
>>> > >  [<ffffffff841e5435>] iput+0xf5/0x180
>>> > >  [<ffffffff841df8a0>] dentry_kill+0x260/0x2d0
>>> > >  [<ffffffff841df97c>] dput+0x6c/0x110
>>> > >  [<ffffffff841c92a9>] __fput+0x189/0x200
>>> > >  [<ffffffff841c936e>] ____fput+0xe/0x10
>>> > >  [<ffffffff84090484>] task_work_run+0xb4/0xe0
>>> > >  [<ffffffff8406ee42>] do_exit+0x302/0xb80
>>> > >  [<ffffffff84349e13>] ? __this_cpu_preempt_check+0x13/0x20
>>> > >  [<ffffffff8407073c>] do_group_exit+0x4c/0xc0
>>> > >  [<ffffffff840707c4>] SyS_exit_group+0x14/0x20
>>> > >  [<ffffffff8475bf64>] tracesys+0xdd/0xe2
>>> > > Code: 4c 89 30 e9 80 fe ff ff 48 8b 75 c0 4c 89 ff e8 82 8f 1c 00 84 c0 0f 85 6c fe ff ff e9 4f fe ff ff 0f 1f 44 00 00 e8 ae 95 5e 00 <0f> 0b e8 04 1c f1 ff 0f 0b 66 90 0f 1f 44 00 00 55 48 89 e5 41
>>> > >
>>> > >
>>> > > --
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>>> > > see: http://www.linux-mm.org/ .
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>> > 
>> > This might shine some light, CONFIG_DEBUG_VM should be =y.
>> > 
>> > --- a/mm/filemap.c
>> > +++ b/mm/filemap.c
>> > @@ -199,7 +199,7 @@ void __delete_from_page_cache(struct page *page,
>> > void *shadow)
>> >         __dec_zone_page_state(page, NR_FILE_PAGES);
>> >         if (PageSwapBacked(page))
>> >                 __dec_zone_page_state(page, NR_SHMEM);
>> > -       BUG_ON(page_mapped(page));
>> > +       VM_BUG_ON_PAGE(page_mapped(page), page);
>> > 
>> >         /*
>> >          * Some filesystems seem to re-dirty the page even after
> Yes, there's a chance that will tell us more (but I don't have high
> hopes of it).  I'm still stumped by this issue, just as before.
> 
> Sasha (or Dave), any update on whether you see this without THP?
> and whether you see the remove_migration_pte oops without THP?

I'm pretty sure at this point that I only see both with THP enabled.

I've started seeing much less of them during fuzzing. Timing changes?


Thanks,
Sasha
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