BUG at fs/jfs/jfs_dmap.c:2983 assert(n < 4)
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kernel BUG at fs/jfs/jfs_dmap.c:2983!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7864 Comm: syz.5.597 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:dbFindLeaf+0x517/0x520 fs/jfs/jfs_dmap.c:2983
Code: fe e9 51 ff ff ff e8 78 06 96 fe 48 c7 c7 a0 fa a5 8a 48 c7 c6 20 f8 a5 8a ba a7 0b 00 00 48 c7 c1 c0 05 a6 8a e8 99 8c 1a 07 <0f> 0b 0f 1f 80 00 00 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec
RSP: 0018:ffffc900048ef2d8 EFLAGS: 00010246
RAX: 000000000000002b RBX: 00000000ffffffff RCX: 40c19792c347df00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffff5200091ddfd
R10: fffff5200091ddfd R11: 1ffff9200091ddfc R12: 0000000000000007
R13: 0000000000000060 R14: 000000000000005d R15: 0000000000000155
FS:  00007f0bd96376c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff4c2ff6000 CR3: 000000002ea80000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dbAllocDmapLev+0x61/0x3c0 fs/jfs/jfs_dmap.c:1969
 dbAlloc+0x988/0xb90 fs/jfs/jfs_dmap.c:844
 extBalloc fs/jfs/jfs_extent.c:326 [inline]
 extAlloc+0x4d2/0xf30 fs/jfs/jfs_extent.c:122
 jfs_get_block+0x343/0xab0 fs/jfs/inode.c:254
 get_more_blocks fs/direct-io.c:659 [inline]
 do_direct_IO fs/direct-io.c:947 [inline]
 __blockdev_direct_IO+0x16a9/0x3450 fs/direct-io.c:1260
 blockdev_direct_IO include/linux/fs.h:3344 [inline]
 jfs_direct_IO+0x119/0x220 fs/jfs/inode.c:342
 generic_file_direct_write+0x10f/0x330 mm/filemap.c:3787
 __generic_file_write_iter+0x15f/0x2a0 mm/filemap.c:3945
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_write+0x62d/0xaf0 fs/read_write.c:861
 vfs_writev fs/read_write.c:934 [inline]
 do_pwritev+0x201/0x340 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0bd878f749
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:00007f0bd9637038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007f0bd89e5fa0 RCX: 00007f0bd878f749
RDX: 0000000000000001 RSI: 0000200000000240 RDI: 0000000000000004
RBP: 00007f0bd8813f91 R08: 0000000000000000 R09: 0000000000000003
R10: 0000000000002000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0bd89e6038 R14: 00007f0bd89e5fa0 R15: 00007ffeb3d01bc8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dbFindLeaf+0x517/0x520 fs/jfs/jfs_dmap.c:2983
Code: fe e9 51 ff ff ff e8 78 06 96 fe 48 c7 c7 a0 fa a5 8a 48 c7 c6 20 f8 a5 8a ba a7 0b 00 00 48 c7 c1 c0 05 a6 8a e8 99 8c 1a 07 <0f> 0b 0f 1f 80 00 00 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec
RSP: 0018:ffffc900048ef2d8 EFLAGS: 00010246
RAX: 000000000000002b RBX: 00000000ffffffff RCX: 40c19792c347df00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffff5200091ddfd
R10: fffff5200091ddfd R11: 1ffff9200091ddfc R12: 0000000000000007
R13: 0000000000000060 R14: 000000000000005d R15: 0000000000000155
FS:  00007f0bd96376c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff3397b7198 CR3: 000000002ea80000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400