------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2809!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 12 Comm: kworker/u4:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:ext4_do_writepages+0x4607/0x4610 fs/ext4/inode.c:2808
Code: c6 a0 b7 7e 8b e8 89 90 af fe 90 0f 0b e8 31 b5 47 ff 4c 89 f7 48 c7 c6 80 bb 7e 8b e8 72 90 af fe 90 0f 0b e8 1a b5 47 ff 90 <0f> 0b 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900001e6ca0 EFLAGS: 00010293
RAX: ffffffff82785e36 RBX: 0000004210000000 RCX: ffff88801ab14900
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc900001e70d0 R08: ffff888036ab5ff7 R09: 1ffff11006d56bfe
R10: dffffc0000000000 R11: ffffed1006d56bff R12: 0000000000000001
R13: ffffc900001e7120 R14: 0000004000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88808d72d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc1c141ff8 CR3: 0000000051357000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
 do_writepages+0x32e/0x550 mm/page-writeback.c:2604
 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1719
 writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:2015
 wb_writeback+0x43b/0xaf0 fs/fs-writeback.c:2195
 wb_do_writeback fs/fs-writeback.c:2342 [inline]
 wb_workfn+0x409/0xef0 fs/fs-writeback.c:2382
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_do_writepages+0x4607/0x4610 fs/ext4/inode.c:2808
Code: c6 a0 b7 7e 8b e8 89 90 af fe 90 0f 0b e8 31 b5 47 ff 4c 89 f7 48 c7 c6 80 bb 7e 8b e8 72 90 af fe 90 0f 0b e8 1a b5 47 ff 90 <0f> 0b 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900001e6ca0 EFLAGS: 00010293
RAX: ffffffff82785e36 RBX: 0000004210000000 RCX: ffff88801ab14900
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc900001e70d0 R08: ffff888036ab5ff7 R09: 1ffff11006d56bfe
R10: dffffc0000000000 R11: ffffed1006d56bff R12: 0000000000000001
R13: ffffc900001e7120 R14: 0000004000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88808d72d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4e072ff000 CR3: 0000000041ed6000 CR4: 0000000000352ef0