kernel BUG at fs/hfs/inode.c:LINE!

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
86bbbebac1933e6e95e8234c4f7d220c5ddd38bc (Mon Apr 2 18:47:07 2018 +0000)
Merge branch 'ras-core-for-linus' of  
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=599e1f94d33497d03385

C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5460031726157824
syzkaller reproducer:  
https://syzkaller.appspot.com/x/repro.syz?id=5078997125824512
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=6017537137442816
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=6801295859785128502
compiler: gcc (GCC) 7.1.1 20170620

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Reported-by: syzbot+599e1f94d33497d03385@xxxxxxxxxxxxxxxxxxxxxxxxx
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IPVS: ftp: loaded support on port[0] = 21
hfs: unable to locate alternate MDB
hfs: continuing without an alternate MDB
------------[ cut here ]------------
kernel BUG at fs/hfs/inode.c:441!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 4.16.0+ #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:hfs_write_inode+0xe6/0xc50 fs/hfs/inode.c:441
RSP: 0018:ffff8801d9466780 EFLAGS: 00010293
RAX: ffff8801d945a5c0 RBX: 1ffff1003b28ccf4 RCX: ffffffff820f97f6
RDX: 0000000000000000 RSI: ffff8801d9466de8 RDI: ffff8801d97b4740
RBP: ffff8801d94668e8 R08: ffffed003b6246c3 R09: ffffed003b6246c3
R10: 0000000000000001 R11: ffffed003b6246c2 R12: ffff8801d97b4700
R13: 0000000000000000 R14: ffff8801d94668c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f233bf15000 CR3: 000000000846a003 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 write_inode fs/fs-writeback.c:1182 [inline]
 __writeback_single_inode+0x9d0/0x1250 fs/fs-writeback.c:1381
 writeback_sb_inodes+0x688/0xff0 fs/fs-writeback.c:1586
 wb_writeback+0x444/0xdb0 fs/fs-writeback.c:1762
 wb_do_writeback fs/fs-writeback.c:1907 [inline]
 wb_workfn+0x2c6/0x15a0 fs/fs-writeback.c:1948
 process_one_work+0xc97/0x1c40 kernel/workqueue.c:2113
 worker_thread+0x1c3/0x1380 kernel/workqueue.c:2247
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
Code: 0f 0f 87 ff 00 00 00 e8 09 91 61 ff 49 83 ff 03 0f 84 58 06 00 00 49  
83 ff 04 74 11 49 83 ff 02 0f 84 e0 00 00 00 e8 ea 90 61 ff <0f> 0b e8 e3  
90 61 ff 49 8d 7c 24 28 48 b8 00 00 00 00 00 fc ff
RIP: hfs_write_inode+0xe6/0xc50 fs/hfs/inode.c:441 RSP: ffff8801d9466780
---[ end trace 58207cc73dd7e339 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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