IPVS: sync thread started: state = BACKUP, mcast_ifn = veth1, syncid = 4, id = 0
------------[ cut here ]------------
kernel BUG at fs/buffer.c:606!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 25317 Comm: syz-executor1 Not tainted 4.9.113-g9905591 #14
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019c8ce000 task.stack: ffff8801cd2a0000
RIP: 0010:[<ffffffff81622397>]  [<ffffffff81622397>] mark_buffer_dirty_inode+0x1a7/0x200 fs/buffer.c:606
RSP: 0018:ffff8801cd2a7a30  EFLAGS: 00010216
RAX: 0000000000040000 RBX: ffff880189635b28 RCX: ffffc9000231b000
RDX: 000000000000a315 RSI: ffffffff81622397 RDI: ffff8801cbe7b280
RBP: ffff8801cd2a7a60 R08: ffff88019c8ce938 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801cbe7b128
R13: ffff8801d61c8f08 R14: 0000000000000000 R15: dffffc0000000000
FS:  00007f979e8e6700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffeaa6c1bd8 CR3: 00000001a32d5000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000000 ffff8801cd2a7c20 ffff8801b1e8e28c 00000000ffffffff
 ffff8801cd2a7c20 dffffc0000000000 ffff8801cd2a7a90 ffffffff818c3ff5
 ffff8801cd2a7a90 ffff8801cd2a7d60 0000000000000000 0000000000000046
Call Trace:
 [<ffffffff818c3ff5>] fat16_ent_put+0xc5/0x100 fs/fat/fatent.c:181
 [<ffffffff818c6f9c>] fat_alloc_clusters+0x5ac/0xe10 fs/fat/fatent.c:499
 [<ffffffff818d40df>] fat_add_cluster+0x6f/0xe0 fs/fat/inode.c:100
 [<ffffffff818c886c>] fat_fallocate+0x23c/0x2d0 fs/fat/file.c:262
 [<ffffffff81568809>] vfs_fallocate+0x359/0x600 fs/open.c:329
 [<ffffffff8156b713>] SYSC_fallocate fs/open.c:352 [inline]
 [<ffffffff8156b713>] SyS_fallocate+0x53/0x90 fs/open.c:346
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fa193>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 4d 4c 89 63 58 4c 89 f7 e8 23 74 3d 02 e9 56 ff ff ff e8 d9 c6 d3 ff <0f> 0b 4c 89 ef e8 7f 98 f1 ff e9 3b ff ff ff e8 75 98 f1 ff e9 
RIP  [<ffffffff81622397>] mark_buffer_dirty_inode+0x1a7/0x200 fs/buffer.c:606
 RSP <ffff8801cd2a7a30>
---[ end trace 89a6adb828a0541e ]---