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

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    d3d1556696c1 Merge tag 'mm-hotfixes-stable-2024-10-09-15-4..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1354cb27980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7a3fccdd0bb995
dashboard link: https://syzkaller.appspot.com/bug?extid=5f7f0caf9979e9d09ff8
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=12f66fd0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12ed005f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ea459972f07f/disk-d3d15566.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b8dcb9ab73d3/vmlinux-d3d15566.xz
kernel image: https://storage.googleapis.com/syzbot-assets/686f1b595c23/bzImage-d3d15566.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/73f0c7d76431/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5f7f0caf9979e9d09ff8@xxxxxxxxxxxxxxxxxxxxxxxxx

loop0: detected capacity change from 0 to 32768
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3624:7
index -1 is out of range for type 'struct dtslot[128]'
CPU: 0 UID: 0 PID: 5218 Comm: syz-executor135 Not tainted 6.12.0-rc2-syzkaller-00074-gd3d1556696c1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429
 dtInsertEntry+0x1735/0x1780 fs/jfs/jfs_dtree.c:3624
 dtInsert+0xbc1/0x6c10 fs/jfs/jfs_dtree.c:893
 jfs_create+0x7ba/0xbb0 fs/jfs/namei.c:137
 lookup_open fs/namei.c:3595 [inline]
 open_last_lookups fs/namei.c:3694 [inline]
 path_openat+0x1c03/0x3590 fs/namei.c:3930
 do_filp_open+0x235/0x490 fs/namei.c:3960
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_open fs/open.c:1438 [inline]
 __se_sys_open fs/open.c:1434 [inline]
 __x64_sys_open+0x225/0x270 fs/open.c:1434
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2b371c0639
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:00007fff164f4418 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fff164f45f8 RCX: 00007f2b371c0639
RDX: 0000000000000000 RSI: 0000000000141042 RDI: 0000000020000000
RBP: 00007f2b37239610 R08: 0000000000005d93 R09: 0000000000000000
R10: 00007fff164f42e0 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fff164f45e8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
---[ end trace ]---


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