BUG at fs/jfs/jfs_dmap.c:3070 assert(n < 4)
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kernel BUG at fs/jfs/jfs_dmap.c:3070!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5322 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:dbFindLeaf+0x519/0x520 fs/jfs/jfs_dmap.c:3070
Code: e9 4e ff ff ff e8 b7 8b 5e fe 48 c7 c7 a0 59 2c 8c 48 c7 c6 e0 56 2c 8c ba fe 0b 00 00 48 c7 c1 c0 64 2c 8c e8 b8 28 bf 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: 0000:ffffc9000f7ee3f0 EFLAGS: 00010246
RAX: 000000000000002b RBX: 00000000ffffffff RCX: 262e6fd9743c9f00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffc9000f7ee167 R09: 1ffff92001efdc2c
R10: dffffc0000000000 R11: fffff52001efdc2d R12: 0000000000000000
R13: 0000000000000159 R14: 000000000000015c R15: 0000000000000555
FS:  0000000000000000(0000) GS:ffff88808c540000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffc0 CR3: 0000000045406000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 dbFindCtl+0x20d/0x4a0 fs/jfs/jfs_dmap.c:1804
 dbAllocAny fs/jfs/jfs_dmap.c:1614 [inline]
 dbAlloc+0x5fc/0xba0 fs/jfs/jfs_dmap.c:965
 extBalloc fs/jfs/jfs_extent.c:336 [inline]
 extAlloc+0x57d/0x1010 fs/jfs/jfs_extent.c:127
 jfs_get_block+0x351/0xad0 fs/jfs/inode.c:254
 __block_write_begin_int+0x6c2/0x1900 fs/buffer.c:2123
 block_write_begin+0x8d/0x120 fs/buffer.c:2234
 jfs_write_begin+0x35/0x80 fs/jfs/inode.c:306
 generic_perform_write+0x2d5/0x8f0 mm/filemap.c:4358
 generic_file_write_iter+0xae/0x330 mm/filemap.c:4501
 __kernel_write_iter+0x44a/0x8f0 fs/read_write.c:621
 dump_emit_page fs/coredump.c:1298 [inline]
 dump_user_range+0xc19/0x12c0 fs/coredump.c:1372
 elf_core_dump+0x3485/0x3a90 fs/binfmt_elf.c:2109
 coredump_write+0x1290/0x1960 fs/coredump.c:1052
 do_coredump fs/coredump.c:1131 [inline]
 vfs_coredump+0x36ff/0x44b0 fs/coredump.c:1200
 get_signal+0x1094/0x12c0 kernel/signal.c:3031
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
 irqentry_exit+0x2ba/0x8f0 kernel/entry/common.c:165
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x7fa27ef9e021
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:ffffffffffffffc0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fa27f225fa0 RCX: 00007fa27ef9e019
RDX: 0000000000000000 RSI: ffffffffffffffc0 RDI: 0000000000180000
RBP: 00007fa27f03500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fa27f226038 R14: 00007fa27f225fa0 R15: 00007ffc5e7e2b18
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dbFindLeaf+0x519/0x520 fs/jfs/jfs_dmap.c:3070
Code: e9 4e ff ff ff e8 b7 8b 5e fe 48 c7 c7 a0 59 2c 8c 48 c7 c6 e0 56 2c 8c ba fe 0b 00 00 48 c7 c1 c0 64 2c 8c e8 b8 28 bf 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: 0000:ffffc9000f7ee3f0 EFLAGS: 00010246
RAX: 000000000000002b RBX: 00000000ffffffff RCX: 262e6fd9743c9f00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffc9000f7ee167 R09: 1ffff92001efdc2c
R10: dffffc0000000000 R11: fffff52001efdc2d R12: 0000000000000000
R13: 0000000000000159 R14: 000000000000015c R15: 0000000000000555
FS:  0000000000000000(0000) GS:ffff88808c540000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffc0 CR3: 0000000045406000 CR4: 0000000000352ef0