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kernel BUG at fs/ext4/inode.c:2803!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 13 Comm: kworker/u4:1 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+0x46d6/0x46e0 fs/ext4/inode.c:2802
Code: c6 a0 1d e4 8b e8 da 21 a0 fe 90 0f 0b e8 b2 b6 3d ff 4c 89 f7 48 c7 c6 80 22 e4 8b e8 c3 21 a0 fe 90 0f 0b e8 9b b6 3d ff 90 <0f> 0b 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000026ec80 EFLAGS: 00010293
RAX: ffffffff8287f8e5 RBX: 0000004a10000000 RCX: ffff88801bb30000
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc9000026f090 R08: ffff888047a826b7 R09: 1ffff11008f504d6
R10: dffffc0000000000 R11: ffffed1008f504d7 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000004000000000 R15: 1ffff11003ea68c7
FS:  0000000000000000(0000) GS:ffff88808ca55000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000020000 CR3: 0000000011d9e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3019
 do_writepages+0x32e/0x550 mm/page-writeback.c:2554
 __writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750
 writeback_sb_inodes+0x992/0x1a20 fs/fs-writeback.c:2042
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
 wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2229
 wb_check_start_all fs/fs-writeback.c:2355 [inline]
 wb_do_writeback fs/fs-writeback.c:2381 [inline]
 wb_workfn+0x95b/0xf50 fs/fs-writeback.c:2414
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 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+0x46d6/0x46e0 fs/ext4/inode.c:2802
Code: c6 a0 1d e4 8b e8 da 21 a0 fe 90 0f 0b e8 b2 b6 3d ff 4c 89 f7 48 c7 c6 80 22 e4 8b e8 c3 21 a0 fe 90 0f 0b e8 9b b6 3d ff 90 <0f> 0b 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000026ec80 EFLAGS: 00010293
RAX: ffffffff8287f8e5 RBX: 0000004a10000000 RCX: ffff88801bb30000
RDX: 0000000000000000 RSI: 0000004000000000 RDI: 0000000000000000
RBP: ffffc9000026f090 R08: ffff888047a826b7 R09: 1ffff11008f504d6
R10: dffffc0000000000 R11: ffffed1008f504d7 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000004000000000 R15: 1ffff11003ea68c7
FS:  0000000000000000(0000) GS:ffff88808ca55000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1bd4427490 CR3: 000000001c294000 CR4: 0000000000352ef0