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kernel BUG at fs/ocfs2/refcounttree.c:2895!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5327 Comm: syz.0.0 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
RIP: 0010:ocfs2_clear_cow_buffer+0x79/0x80 fs/ocfs2/refcounttree.c:2895
Code: 02 75 21 e8 79 c3 db fd 48 89 df be 08 00 00 00 e8 dc f6 4a fe 3e 80 23 ef 31 c0 5b 41 5e c3 cc cc cc cc cc e8 58 c3 db fd 90 <0f> 0b 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000f73f1d8 EFLAGS: 00010287
RAX: ffffffff83eb50f8 RBX: ffff888044207620 RCX: 0000000000100000
RDX: ffffc90020001000 RSI: 00000000000004a8 RDI: 00000000000004a9
RBP: 0000000000000001 R08: ffff888044207627 R09: 1ffff11008840ec4
R10: dffffc0000000000 R11: ffffed1008840ec5 R12: ffff888044207620
R13: ffff888044207700 R14: 0000000000000002 R15: 0000000000001000
FS:  00007ff25326c6c0(0000) GS:ffff88808c543000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff2475bd000 CR3: 0000000043925000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 walk_page_buffers+0x94/0x1e0 fs/ocfs2/aops.c:421
 ocfs2_duplicate_clusters_by_page+0x70b/0xcd0 fs/ocfs2/refcounttree.c:2974
 ocfs2_replace_clusters fs/ocfs2/refcounttree.c:3125 [inline]
 ocfs2_make_clusters_writable fs/ocfs2/refcounttree.c:3257 [inline]
 ocfs2_replace_cow+0xaf4/0x1c90 fs/ocfs2/refcounttree.c:3351
 ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3429 [inline]
 ocfs2_refcount_cow+0x790/0xd40 fs/ocfs2/refcounttree.c:3472
 ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2352 [inline]
 ocfs2_file_write_iter+0xf26/0x1f10 fs/ocfs2/file.c:2463
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x612/0xba0 fs/read_write.c:687
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff25239de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff25326bfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff252626090 RCX: 00007ff25239de99
RDX: 0000000000000020 RSI: 00002000000007c0 RDI: 0000000000000006
RBP: 00007ff252433eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff252626128 R14: 00007ff252626090 R15: 00007fff306c1538
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ocfs2_clear_cow_buffer+0x79/0x80 fs/ocfs2/refcounttree.c:2895
Code: 02 75 21 e8 79 c3 db fd 48 89 df be 08 00 00 00 e8 dc f6 4a fe 3e 80 23 ef 31 c0 5b 41 5e c3 cc cc cc cc cc e8 58 c3 db fd 90 <0f> 0b 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000f73f1d8 EFLAGS: 00010287
RAX: ffffffff83eb50f8 RBX: ffff888044207620 RCX: 0000000000100000
RDX: ffffc90020001000 RSI: 00000000000004a8 RDI: 00000000000004a9
RBP: 0000000000000001 R08: ffff888044207627 R09: 1ffff11008840ec4
R10: dffffc0000000000 R11: ffffed1008840ec5 R12: ffff888044207620
R13: ffff888044207700 R14: 0000000000000002 R15: 0000000000001000
FS:  00007ff25326c6c0(0000) GS:ffff88808c543000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff2475bd000 CR3: 0000000043925000 CR4: 0000000000352ef0