[syzbot] [jfs?] UBSAN: array-index-out-of-bounds in jfs_readdir

syzbot
2024-04-01T14:07:26Z

Hello,

syzbot found the following issue on:

HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1723f529180000
kernel config: https://syzkaller.appspot.com/x/.config?x=4d90a36f0cab495a
dashboard link: https://syzkaller.appspot.com/bug?extid=0315f8fe99120601ba88
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1574d855180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d95219180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/72ab73815344/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d6d6b0d7071/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/48e275e5478b/bzImage-fe46a7dd.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/fe45a050e301/mount_0.gz

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12f6203d180000
final oops: https://syzkaller.appspot.com/x/report.txt?x=11f6203d180000
console output: https://syzkaller.appspot.com/x/log.txt?x=16f6203d180000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0315f8fe99120601ba88@syzkaller.appspotmail.com

------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:2892:30
index -1 is out of range for type 'struct dtslot[128]'
CPU: 0 PID: 5057 Comm: syz-executor163 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
ubsan_epilogue lib/ubsan.c:217 [inline]
__ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:415
jfs_readdir+0x1cb4/0x4660 fs/jfs/jfs_dtree.c:2892
wrap_directory_iterator+0x94/0xe0 fs/readdir.c:67
iterate_dir+0x539/0x6f0 fs/readdir.c:110
__do_sys_getdents64 fs/readdir.c:409 [inline]
__se_sys_getdents64+0x20d/0x4f0 fs/readdir.c:394
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f00e0f665f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffdc32b878 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007fffdc32ba48 RCX: 00007f00e0f665f9
RDX: 000000000000102a RSI: 0000000020002280 RDI: 0000000000000004
RBP: 00007f00e0fdf610 R08: 0000000000000000 R09: 00007fffdc32ba48
R10: 00000000000060cc R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffdc32ba38 R14: 0000000000000001 R15: 0000000000000001
</TASK>
---[ end trace ]---

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