BUG at fs/jfs/jfs_dmap.c:2983 assert(n < 4)
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kernel BUG at fs/jfs/jfs_dmap.c:2983!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6843 Comm: syz.7.95 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:dbFindLeaf+0x51d/0x520
Code: e9 4c ff ff ff e8 33 b0 80 fe 48 c7 c7 00 e3 c3 8b 48 c7 c6 40 e0 c3 8b ba a7 0b 00 00 48 c7 c1 c0 ed c3 8b e8 24 a2 e8 fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57
RSP: 0018:ffffc90004246c70 EFLAGS: 00010246
RAX: 000000000000002b RBX: 00000000ffffffff RCX: 1ef49c319567a700
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffffc90004246987 R09: 1ffff92000848d30
R10: dffffc0000000000 R11: fffff52000848d31 R12: 0000000000000004
R13: 0000000000000060 R14: 000000000000005d R15: 0000000000000555
FS:  00007fef1d7706c0(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef12931000 CR3: 00000000327e6000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 dbFindCtl+0x267/0x520
 dbAlloc+0x5fa/0xba0
 extAlloc+0x54a/0xfb0
 jfs_get_block+0x346/0xab0
 __blockdev_direct_IO+0x16ff/0x3490
 jfs_direct_IO+0x119/0x220
 generic_file_direct_write+0x1db/0x3e0
 __generic_file_write_iter+0x11d/0x230
 generic_file_write_iter+0x117/0x550
 iter_file_splice_write+0x975/0x10e0
 direct_splice_actor+0x101/0x160
 splice_direct_to_actor+0x5a8/0xcc0
 do_splice_direct+0x181/0x270
 do_sendfile+0x4da/0x7e0
 __se_sys_sendfile64+0x13e/0x190
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fef1c98ec29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fef1d770038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fef1cbd5fa0 RCX: 00007fef1c98ec29
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007fef1ca11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe85 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fef1cbd6038 R14: 00007fef1cbd5fa0 R15: 00007fffe30bba58
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dbFindLeaf+0x51d/0x520
Code: e9 4c ff ff ff e8 33 b0 80 fe 48 c7 c7 00 e3 c3 8b 48 c7 c6 40 e0 c3 8b ba a7 0b 00 00 48 c7 c1 c0 ed c3 8b e8 24 a2 e8 fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57
RSP: 0018:ffffc90004246c70 EFLAGS: 00010246
RAX: 000000000000002b RBX: 00000000ffffffff RCX: 1ef49c319567a700
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffffc90004246987 R09: 1ffff92000848d30
R10: dffffc0000000000 R11: fffff52000848d31 R12: 0000000000000004
R13: 0000000000000060 R14: 000000000000005d R15: 0000000000000555
FS:  00007fef1d7706c0(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffee7076c48 CR3: 00000000327e6000 CR4: 00000000000006f0
