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: 0 PID: 11000 Comm: syz.2.901 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:dbFindLeaf+0x517/0x520 fs/jfs/jfs_dmap.c:2983
Code: fe e9 51 ff ff ff e8 f8 81 83 fe 48 c7 c7 e0 dc 03 8b 48 c7 c6 20 da 03 8b ba a7 0b 00 00 48 c7 c1 c0 e7 03 8b e8 39 de 76 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:ffffc900042e6d78 EFLAGS: 00010246
RAX: 000000000000002b RBX: 0000000000000000 RCX: 6adf6a9dd9504f00
RDX: ffffc9000e171000 RSI: 0000000000046e7f RDI: 0000000000046e80
RBP: 0000000000000003 R08: ffffc900042e6a87 R09: 1ffff9200085cd50
R10: dffffc0000000000 R11: fffff5200085cd51 R12: 0000000000000004
R13: 0000000000000008 R14: 0000000000000005 R15: 0000000000000155
FS:  00007f71c7ff16c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe2c4050e8 CR3: 000000002e79b000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 dbAllocDmapLev+0x61/0x3c0 fs/jfs/jfs_dmap.c:1969
 dbAllocCtl+0x148/0x9b0 fs/jfs/jfs_dmap.c:1825
 dbAllocAny fs/jfs/jfs_dmap.c:1532 [inline]
 dbAlloc+0x641/0xba0 fs/jfs/jfs_dmap.c:878
 extBalloc fs/jfs/jfs_extent.c:326 [inline]
 extAlloc+0x500/0xf90 fs/jfs/jfs_extent.c:122
 jfs_get_block+0x359/0xad0 fs/jfs/inode.c:254
 get_more_blocks fs/direct-io.c:647 [inline]
 do_direct_IO fs/direct-io.c:935 [inline]
 __blockdev_direct_IO+0x1775/0x3500 fs/direct-io.c:1248
 blockdev_direct_IO include/linux/fs.h:3047 [inline]
 jfs_direct_IO+0x11b/0x220 fs/jfs/inode.c:337
 generic_file_direct_write+0x1d4/0x3e0 mm/filemap.c:3956
 __generic_file_write_iter+0x11b/0x230 mm/filemap.c:4112
 generic_file_write_iter+0xaf/0x2e0 mm/filemap.c:4152
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_write+0x738/0xc30 fs/read_write.c:860
 iter_file_splice_write+0x6a3/0xcb0 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0xe8/0x130 fs/splice.c:1142
 splice_direct_to_actor+0x304/0x8c0 fs/splice.c:1088
 do_splice_direct+0x1d5/0x2f0 fs/splice.c:1194
 do_sendfile+0x5f2/0xef0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64+0x145/0x1a0 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f71c719c819
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:00007f71c7ff1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f71c7415fa0 RCX: 00007f71c719c819
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007f71c7232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f71c7416038 R14: 00007f71c7415fa0 R15: 00007ffe6c9918b8
 </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 f8 81 83 fe 48 c7 c7 e0 dc 03 8b 48 c7 c6 20 da 03 8b ba a7 0b 00 00 48 c7 c1 c0 e7 03 8b e8 39 de 76 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:ffffc900042e6d78 EFLAGS: 00010246
RAX: 000000000000002b RBX: 0000000000000000 RCX: 6adf6a9dd9504f00
RDX: ffffc9000e171000 RSI: 0000000000046e7f RDI: 0000000000046e80
RBP: 0000000000000003 R08: ffffc900042e6a87 R09: 1ffff9200085cd50
R10: dffffc0000000000 R11: fffff5200085cd51 R12: 0000000000000004
R13: 0000000000000008 R14: 0000000000000005 R15: 0000000000000155
FS:  00007f71c7ff16c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa6f13be000 CR3: 000000002e79b000 CR4: 00000000003506f0