------------[ cut here ]------------
kernel BUG at fs/ext4/inode.c:2816!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 181 Comm: kworker/u4:7 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:ext4_do_writepages+0x4768/0x4770 fs/ext4/inode.c:2815
Code: c6 20 2b 26 8c e8 f8 51 95 fe 90 0f 0b e8 f0 4f 35 ff 4c 89 f7 48 c7 c6 00 30 26 8c e8 e1 51 95 fe 90 0f 0b e8 d9 4f 35 ff 90 <0f> 0b 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900018bec60 EFLAGS: 00010293
RAX: ffffffff8292d087 RBX: 0000004210000000 RCX: ffff888033638000
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc900018bf070 R08: ffff8880426f8967 R09: 1ffff110084df12c
R10: dffffc0000000000 R11: ffffed10084df12d R12: ffff88801d06fc60
R13: dffffc0000000000 R14: 0000004000000000 R15: ffff8880426f8b50
FS:  0000000000000000(0000) GS:ffff88808c2bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f00c6147000 CR3: 0000000043b20000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3032
 do_writepages+0x338/0x560 mm/page-writeback.c:2560
 __writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1803
 writeback_sb_inodes+0x9de/0x1b00 fs/fs-writeback.c:2114
 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2190
 wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2301
 wb_check_start_all fs/fs-writeback.c:2427 [inline]
 wb_do_writeback fs/fs-writeback.c:2474 [inline]
 wb_workfn+0x980/0x10f0 fs/fs-writeback.c:2512
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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+0x4768/0x4770 fs/ext4/inode.c:2815
Code: c6 20 2b 26 8c e8 f8 51 95 fe 90 0f 0b e8 f0 4f 35 ff 4c 89 f7 48 c7 c6 00 30 26 8c e8 e1 51 95 fe 90 0f 0b e8 d9 4f 35 ff 90 <0f> 0b 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900018bec60 EFLAGS: 00010293
RAX: ffffffff8292d087 RBX: 0000004210000000 RCX: ffff888033638000
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc900018bf070 R08: ffff8880426f8967 R09: 1ffff110084df12c
R10: dffffc0000000000 R11: ffffed10084df12d R12: ffff88801d06fc60
R13: dffffc0000000000 R14: 0000004000000000 R15: ffff8880426f8b50
FS:  0000000000000000(0000) GS:ffff88808c2bb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe17fbb8700 CR3: 0000000011ff4000 CR4: 0000000000352ef0