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kernel BUG at fs/ext4/inode.c:2812!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 74 Comm: kworker/u32:4 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+0x2e69/0x3f50 fs/ext4/inode.c:2812
Code: a5 10 ff ff ff 48 c1 ea 03 80 3c 02 00 0f 84 c6 e7 ff ff 48 8b bd 28 ff ff ff e8 92 2b a4 ff e9 b5 e7 ff ff e8 08 97 37 ff 90 <0f> 0b e8 00 97 37 ff 89 9d f8 fe ff ff 44 0f b6 ad a3 fe ff ff e9
RSP: 0018:ffffc9000164f260 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88803f3f1d18 RCX: ffffffff82d14391
RDX: ffff8880231924c0 RSI: ffffffff82d16098 RDI: ffff8880231924c0
RBP: ffffc9000164f430 R08: 0000000000000007 R09: 0000000000000000
R10: 0000004000000000 R11: 0000000000000080 R12: 0000000000000001
R13: ffff88803f3f1f60 R14: 1ffff920002c9e6c R15: ffffc9000164f480
FS:  0000000000000000(0000) GS:ffff8880d6338000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2217ba2286 CR3: 000000000e598000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ext4_writepages+0x347/0x790 fs/ext4/inode.c:3029
 do_writepages+0x278/0x600 mm/page-writeback.c:2575
 __writeback_single_inode+0x164/0x13c0 fs/fs-writeback.c:1762
 writeback_sb_inodes+0x766/0x1c70 fs/fs-writeback.c:2054
 wb_writeback+0x1c0/0xbe0 fs/fs-writeback.c:2239
 wb_do_writeback fs/fs-writeback.c:2386 [inline]
 wb_workfn+0x142/0xc00 fs/fs-writeback.c:2426
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 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+0x2e69/0x3f50 fs/ext4/inode.c:2812
Code: a5 10 ff ff ff 48 c1 ea 03 80 3c 02 00 0f 84 c6 e7 ff ff 48 8b bd 28 ff ff ff e8 92 2b a4 ff e9 b5 e7 ff ff e8 08 97 37 ff 90 <0f> 0b e8 00 97 37 ff 89 9d f8 fe ff ff 44 0f b6 ad a3 fe ff ff e9
RSP: 0018:ffffc9000164f260 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88803f3f1d18 RCX: ffffffff82d14391
RDX: ffff8880231924c0 RSI: ffffffff82d16098 RDI: ffff8880231924c0
RBP: ffffc9000164f430 R08: 0000000000000007 R09: 0000000000000000
R10: 0000004000000000 R11: 0000000000000080 R12: 0000000000000001
R13: ffff88803f3f1f60 R14: 1ffff920002c9e6c R15: ffffc9000164f480
FS:  0000000000000000(0000) GS:ffff8880d6338000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2217ba2286 CR3: 000000000e598000 CR4: 0000000000352ef0