kernel BUG at fs/ext4/inode.c:LINE!

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f2ecb86 Linux 4.14.212
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15bc221f500000
kernel config: https://syzkaller.appspot.com/x/.config?x=80549830ca6ffbb2
dashboard link: https://syzkaller.appspot.com/bug?extid=ea5f5548b2cb99b8955c
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10f2ffbd500000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=104f60db500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ea5f55...@syzkaller.appspotmail.com

EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
audit: type=1800 audit(1608868146.719:2): pid=7969 uid=0 auid=0 ses=5 op="collect_data" cause="failed(directio)" comm="syz-executor097" name="file0" dev="loop0" ino=17 res=0
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kernel BUG at fs/ext4/inode.c:2814!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 7969 Comm: syz-executor097 Not tainted 4.14.212-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888096f9e240 task.stack: ffff888096f38000
RIP: 0010:ext4_writepages+0x27fc/0x32a0 fs/ext4/inode.c:2814
RSP: 0018:ffff888096f3f638 EFLAGS: 00010297
RAX: ffff888096f9e240 RBX: 00000000a802c010 RCX: 1ffff11012df3e49
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff888096f9f248
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000001c92
R10: 0000000000000001 R11: ffff888096f9e240 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff88808e326870 R15: ffff888096f3fa60
FS: 0000000000b18880(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055dc813008a0 CR3: 00000000a3006000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
do_writepages+0xc3/0x240 mm/page-writeback.c:2361
__filemap_fdatawrite_range+0x236/0x310 mm/filemap.c:346
file_write_and_wait_range+0x86/0xd0 mm/filemap.c:678
__generic_file_fsync+0x70/0x190 fs/libfs.c:985
ext4_sync_file+0x8ed/0x12c0 fs/ext4/fsync.c:118
vfs_fsync_range+0x103/0x260 fs/sync.c:196
generic_write_sync include/linux/fs.h:2682 [inline]
ext4_file_write_iter+0x5fa/0xd20 fs/ext4/file.c:281
call_write_iter include/linux/fs.h:1778 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x44c/0x630 fs/read_write.c:482
vfs_write+0x17f/0x4d0 fs/read_write.c:544
SYSC_write fs/read_write.c:590 [inline]
SyS_write+0xf2/0x210 fs/read_write.c:582
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x444639
RSP: 002b:00007ffd490d16c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444639
RDX: 0000000000000082 RSI: 0000000020000180 RDI: 0000000000000004
RBP: 00000000006d0018 R08: 00000000004002e0 R09: 00000000004002e0
R10: 00000000004002e0 R11: 0000000000000246 R12: 0000000000402220
R13: 00000000004022b0 R14: 0000000000000000 R15: 0000000000000000
Code: ff ff 4c 89 ff e8 c5 de c2 ff e9 98 db ff ff e8 5b 0e 99 ff 48 8b bc 24 b8 00 00 00 e8 fe 97 b0 ff e9 18 f5 ff ff e8 44 0e 99 ff <0f> 0b e8 3d 0e 99 ff 48 8b bc 24 b8 00 00 00 e8 e0 97 b0 ff 8b
RIP: ext4_writepages+0x27fc/0x32a0 fs/ext4/inode.c:2814 RSP: ffff888096f3f638
---[ end trace 817ffaeed9909b4b ]---


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