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UBSAN: array-index-out-of-bounds in diAllocBit

Status: upstream: reported on 2025/11/19 05:43
Subsystems: jfs
[Documentation on labels]
Reported-by: syzbot+015483fc71d1413f40ee@syzkaller.appspotmail.com
First crash: 6d22h, last: 1d01h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [jfs?] UBSAN: array-index-out-of-bounds in diAllocBit 0 (1) 2025/11/19 05:43

Sample crash report:
loop0: detected capacity change from 0 to 32768
ialloc: diAlloc returned -5!
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_imap.c:2105:2
index 8592359 is out of range for type 'struct iagctl[128]'
CPU: 0 UID: 0 PID: 5324 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~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe9/0xf0 lib/ubsan.c:455
 diAllocBit+0xba2/0xd40 fs/jfs/jfs_imap.c:2105
 diAllocIno fs/jfs/jfs_imap.c:1844 [inline]
 diAllocAG+0x12d9/0x1df0 fs/jfs/jfs_imap.c:1676
 diAlloc+0x1d5/0x1680 fs/jfs/jfs_imap.c:1590
 ialloc+0x8c/0x8f0 fs/jfs/jfs_inode.c:56
 jfs_create+0x18d/0xa80 fs/jfs/namei.c:92
 lookup_open fs/namei.c:3796 [inline]
 open_last_lookups fs/namei.c:3895 [inline]
 path_openat+0x14f4/0x3830 fs/namei.c:4131
 do_filp_open+0x1fa/0x410 fs/namei.c:4161
 do_sys_openat2+0x121/0x1c0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1df898f749
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:00007f1df9762038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f1df8be5fa0 RCX: 00007f1df898f749
RDX: 000000000000275a RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007f1df8a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1df8be6038 R14: 00007f1df8be5fa0 R15: 00007ffc2da154f8
 </TASK>
---[ end trace ]---

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/21 02:44 upstream 8e621c9a3375 280ea308 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in diAllocBit
2025/11/15 11:43 upstream 7a0892d2836e f7988ea4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in diAllocBit
2025/11/15 05:35 upstream 7a0892d2836e f7988ea4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: array-index-out-of-bounds in diAllocBit
* Struck through repros no longer work on HEAD.