kernel BUG at mm/filemap.c:LINE!

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 94a47529a645 Add linux-next specific files for 20190222
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16ffc0ccc00000
kernel config: https://syzkaller.appspot.com/x/.config?x=51cd1c8c39e8a207
dashboard link: https://syzkaller.appspot.com/bug?extid=6712b3ced78acc4e74a6
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [ak...@linux-foundation.org darric...@oracle.com
han...@cmpxchg.org hu...@google.com ja...@suse.cz jo...@toxicpanda.com
jrdr....@gmail.com linux-...@vger.kernel.org linu...@kvack.org
rp...@linux.ibm.com s...@canb.auug.org.au wi...@infradead.org]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6712b3...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at mm/filemap.c:1306!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 5.0.0-rc7-next-20190222 #41
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:end_page_writeback+0x4b8/0x4f0 mm/filemap.c:1306
Code: ef e8 8c f2 1d 00 e9 97 fc ff ff 48 89 df e8 7f f2 1d 00 e9 07 fd ff
ff 4c 89 ef e8 72 f2 1d 00 e9 b8 fc ff ff e8 58 21 e6 ff <0f> 0b 4c 89 ef
e8 5e f2 1d 00 e9 22 fd ff ff 4c 89 ef e8 51 f2 1d
RSP: 0018:ffff8880aa26fad8 EFLAGS: 00010206
RAX: ffff8880aa25c240 RBX: 0000000000000000 RCX: ffffffff818a31b5
RDX: 0000000000000100 RSI: ffffffff818a3438 RDI: 0000000000000005
RBP: ffff8880aa26fb00 R08: ffff8880aa25c240 R09: 0000000000000001
R10: ffffed1015d05bc7 R11: ffff8880ae82de3b R12: ffffea0001cd3b00
R13: ffffea0001cd3b08 R14: 0000000000000000 R15: ffffea0001cd9788
FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa6c555bdb8 CR3: 000000008fcf9000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
page_endio+0x3c8/0x780 mm/filemap.c:1336
mpage_end_io+0x1a5/0x320 fs/mpage.c:55
bio_endio+0x5f8/0xad0 block/bio.c:1849
req_bio_endio block/blk-core.c:196 [inline]
blk_update_request+0x317/0xba0 block/blk-core.c:1457
blk_mq_end_request+0x5b/0x550 block/blk-mq.c:558
lo_complete_rq+0x210/0x2e0 drivers/block/loop.c:485
blk_done_softirq+0x304/0x4d0 block/blk-softirq.c:37
__do_softirq+0x266/0x95a kernel/softirq.c:293
run_ksoftirqd kernel/softirq.c:655 [inline]
run_ksoftirqd+0x8e/0x110 kernel/softirq.c:647
smpboot_thread_fn+0x6ab/0xa10 kernel/smpboot.c:164
kthread+0x357/0x430 kernel/kthread.c:253
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Modules linked in:
---[ end trace 5a42ceebefd403af ]---
RIP: 0010:end_page_writeback+0x4b8/0x4f0 mm/filemap.c:1306
Code: ef e8 8c f2 1d 00 e9 97 fc ff ff 48 89 df e8 7f f2 1d 00 e9 07 fd ff
ff 4c 89 ef e8 72 f2 1d 00 e9 b8 fc ff ff e8 58 21 e6 ff <0f> 0b 4c 89 ef
e8 5e f2 1d 00 e9 22 fd ff ff 4c 89 ef e8 51 f2 1d
RSP: 0018:ffff8880aa26fad8 EFLAGS: 00010206
RAX: ffff8880aa25c240 RBX: 0000000000000000 RCX: ffffffff818a31b5
RDX: 0000000000000100 RSI: ffffffff818a3438 RDI: 0000000000000005
RBP: ffff8880aa26fb00 R08: ffff8880aa25c240 R09: 0000000000000001
R10: ffffed1015d05bc7 R11: ffff8880ae82de3b R12: ffffea0001cd3b00
R13: ffffea0001cd3b08 R14: 0000000000000000 R15: ffffea0001cd9788
FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa6c555bdb8 CR3: 000000008fcf9000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.