syzbot


UBSAN: array-index-out-of-bounds in dbFindLeaf (2)

Status: upstream: reported C repro on 2026/01/08 13:00
Subsystems: jfs
[Documentation on labels]
Reported-by: syzbot+1afe7ef2d0062e19eeb3@syzkaller.appspotmail.com
First crash: 12d, last: 12d
Cause bisection: failed (error log, bisect log)
  
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] jfs: fix oob in dbFindLeaf 1 (1) 2026/01/08 14:45
[syzbot] [jfs?] UBSAN: array-index-out-of-bounds in dbFindLeaf (2) 0 (1) 2026/01/08 13:00
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream UBSAN: array-index-out-of-bounds in dbFindLeaf jfs 15 C error 6 860d 1174d 25/29 fixed on 2023/12/21 03:45
linux-6.1 UBSAN: array-index-out-of-bounds in dbFindLeaf 15 1 933d 933d 0/3 auto-obsoleted due to no activity on 2023/10/08 15:35

Sample crash report:
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:2976:16
index 1365 is out of range for type 's8[1365]' (aka 'signed char[1365]')
CPU: 1 UID: 0 PID: 6059 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe9/0xf0 lib/ubsan.c:455
 dbFindLeaf+0x308/0x520 fs/jfs/jfs_dmap.c:2976
 dbFindCtl+0x267/0x520 fs/jfs/jfs_dmap.c:1717
 dbAllocAny fs/jfs/jfs_dmap.c:1527 [inline]
 dbAlloc+0x5fa/0xba0 fs/jfs/jfs_dmap.c:878
 diNewIAG fs/jfs/jfs_imap.c:2510 [inline]
 diAllocExt fs/jfs/jfs_imap.c:1905 [inline]
 diAllocAG+0xd45/0x1df0 fs/jfs/jfs_imap.c:1669
 diAlloc+0x1d4/0x1670 fs/jfs/jfs_imap.c:1590
 ialloc+0x8c/0x8f0 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x193/0xa70 fs/jfs/namei.c:225
 vfs_mkdir+0x52d/0x5d0 fs/namei.c:5130
 do_mkdirat+0x27a/0x4b0 fs/namei.c:5164
 __do_sys_mkdirat fs/namei.c:5186 [inline]
 __se_sys_mkdirat fs/namei.c:5184 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:5184
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe6c5ade97
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 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:00007efe6bbf4e68 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007efe6bbf4ef0 RCX: 00007efe6c5ade97
RDX: 00000000000001ff RSI: 00002000000002c0 RDI: 00000000ffffff9c
RBP: 0000200000000200 R08: 00002000000000c0 R09: 0000000000000000
R10: 0000200000000200 R11: 0000000000000246 R12: 00002000000002c0
R13: 00007efe6bbf4eb0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
---[ end trace ]---

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/07 01:47 upstream f0b9d8eb98df d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs UBSAN: array-index-out-of-bounds in dbFindLeaf
2026/01/07 00:45 upstream f0b9d8eb98df d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs UBSAN: array-index-out-of-bounds in dbFindLeaf
2026/01/06 23:43 upstream f0b9d8eb98df d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs UBSAN: array-index-out-of-bounds in dbFindLeaf
2026/01/06 22:59 upstream f0b9d8eb98df d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs UBSAN: array-index-out-of-bounds in dbFindLeaf
2026/01/06 22:04 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs UBSAN: array-index-out-of-bounds in dbFindLeaf
* Struck through repros no longer work on HEAD.