Re: [syzbot] [jfs?] KASAN: slab-use-after-free Write in dtSplitPage

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    d6ef8b40d075 Merge tag 'sound-6.13-rc5' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16ddd90f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=743927383a52aa3d
dashboard link: https://syzkaller.appspot.com/bug?extid=a939a1121380d3212940
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1346e0b0580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fbe05b4b2f4e/disk-d6ef8b40.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cd60b8a08817/vmlinux-d6ef8b40.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d8b74baeeae9/bzImage-d6ef8b40.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a8b14cacf8f6/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a939a1121380d3212940@xxxxxxxxxxxxxxxxxxxxxxxxx

loop2: detected capacity change from 0 to 32768
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1600:21
index 26 is out of range for type 'lv [20]'
CPU: 1 UID: 0 PID: 6600 Comm: syz.2.264 Not tainted 6.13.0-rc4-syzkaller-00054-gd6ef8b40d075 #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+0x16c/0x1f0 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_out_of_bounds+0x110/0x150 lib/ubsan.c:429
 dtSplitPage+0x387f/0x3930 fs/jfs/jfs_dtree.c:1600
 dtSplitUp+0x7da/0x5840 fs/jfs/jfs_dtree.c:1091
 dtInsert+0x8c5/0xb40 fs/jfs/jfs_dtree.c:870
 jfs_rename+0x10a8/0x1820 fs/jfs/namei.c:1225
 vfs_rename+0xf8b/0x21f0 fs/namei.c:5067
 do_renameat2+0xc5f/0xdd0 fs/namei.c:5224
 __do_sys_rename fs/namei.c:5271 [inline]
 __se_sys_rename fs/namei.c:5269 [inline]
 __x64_sys_rename+0x7d/0xa0 fs/namei.c:5269
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdcb5585d29
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:00007fdcb6401038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007fdcb5775fa0 RCX: 00007fdcb5585d29
RDX: 0000000000000000 RSI: 0000000020000f40 RDI: 0000000020000300
RBP: 00007fdcb5601b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fdcb5775fa0 R15: 00007ffe75efbb88
 </TASK>
---[ end trace ]---


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