kernel BUG at fs/f2fs/segment.c:LINE!

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f79dc860 Linux 4.14.215
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10d79548d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9844af499cbb61c0
dashboard link: https://syzkaller.appspot.com/bug?extid=5afeedb769eeba68ae13
compiler: gcc (GCC) 10.1.0-syz 20200507

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5afeed...@syzkaller.appspotmail.com

batman_adv: Cannot find parent device
batman_adv: Cannot find parent device
F2FS-fs (loop5): Bitmap was wrongly cleared, blk:5121
------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.c:1705!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 32 Comm: kworker/u4:2 Not tainted 4.14.215-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-7:5)
task: ffff8880b5684140 task.stack: ffff8880b5688000
RIP: 0010:update_sit_entry+0x1107/0x1540 fs/f2fs/segment.c:1705
RSP: 0018:ffff8880b568f198 EFLAGS: 00010282
RAX: dffffc0000000000 RBX: ffff88809a05c5c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880b5684a40 RDI: ffffed1016ad1e0d
RBP: ffff8880a2b0cac0 R08: 0000000000000035 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000001401
R13: 00000000ffffffff R14: 0000000000000000 R15: 0000000000000040
FS: 0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93bcb869d0 CR3: 000000009cede000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
refresh_sit_entry+0x158/0x730 fs/f2fs/segment.c:1730
allocate_data_block+0x47d/0xf60 fs/f2fs/segment.c:2372
do_write_page+0x222/0x7f0 fs/f2fs/segment.c:2402
write_data_page+0x15d/0x3a0 fs/f2fs/segment.c:2456
do_write_data_page+0xc63/0x2ca0 fs/f2fs/data.c:1493
__write_data_page+0x1147/0x1470 fs/f2fs/data.c:1567
f2fs_write_cache_pages+0x40d/0xe50 fs/f2fs/data.c:1744
__f2fs_write_data_pages+0x2e2/0xb90 fs/f2fs/data.c:1838
do_writepages+0xc3/0x240 mm/page-writeback.c:2361
__writeback_single_inode+0xda/0x1150 fs/fs-writeback.c:1379
writeback_sb_inodes+0x48b/0xd30 fs/fs-writeback.c:1643
wb_writeback+0x243/0xb80 fs/fs-writeback.c:1816
wb_do_writeback fs/fs-writeback.c:1948 [inline]
wb_workfn+0x2a1/0xef0 fs/fs-writeback.c:1984
process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 3e f9 ff 0f 0b 4c 89 04 24 e8 96 7b 84 fe 4c 8b 04 24 44 89 e1 48 c7 c2 40 4a c2 87 48 c7 c6 00 49 c2 87 4c 89 c7 e8 a9 3e f9 ff <0f> 0b 4c 89 f7 e8 ef 67 ae fe e9 43 f0 ff ff e8 e5 67 ae fe e9
RIP: update_sit_entry+0x1107/0x1540 fs/f2fs/segment.c:1705 RSP: ffff8880b568f198
---[ end trace 14264795b8ddff0b ]---


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[syzbot]

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