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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    7846b618e0a4 Merge tag 'rtc-6.11' of git://git.kernel.org/..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=169ade0d980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f4925140c45a2a50
dashboard link: https://syzkaller.appspot.com/bug?extid=dca05492eff41f604890
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=165876b5980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1453ee95980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/43e8dc30bfe7/disk-7846b618.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2563411f0b58/vmlinux-7846b618.xz
kernel image: https://storage.googleapis.com/syzbot-assets/19d3b69b2212/bzImage-7846b618.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/97777a7e85e9/mount_0.gz

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

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13f21c65980000
console output: https://syzkaller.appspot.com/x/log.txt?x=17f21c65980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dca05492eff41f604890@xxxxxxxxxxxxxxxxxxxxxxxxx

loop0: detected capacity change from 0 to 32768
loop0: detected capacity change from 32768 to 32745
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:2628:27
index 4294967295 is out of range for type 's8[1365]' (aka 'signed char[1365]')
CPU: 0 PID: 5087 Comm: syz-executor157 Not tainted 6.10.0-syzkaller-11323-g7846b618e0a4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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:231 [inline]
 __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429
 dbSplit+0x1fd/0x220 fs/jfs/jfs_dmap.c:2628
 dbAllocBits+0x4e5/0x9a0 fs/jfs/jfs_dmap.c:2191
 dbAllocDmap fs/jfs/jfs_dmap.c:2032 [inline]
 dbAllocDmapLev+0x250/0x4a0 fs/jfs/jfs_dmap.c:1986
 dbAllocCtl+0x113/0x920 fs/jfs/jfs_dmap.c:1823
 dbAllocAG+0x28f/0x10b0 fs/jfs/jfs_dmap.c:1364
 dbAlloc+0x658/0xca0 fs/jfs/jfs_dmap.c:888
 dtSplitUp fs/jfs/jfs_dtree.c:979 [inline]
 dtInsert+0xda7/0x6b00 fs/jfs/jfs_dtree.c:868
 jfs_create+0x7ba/0xbb0 fs/jfs/namei.c:137
 lookup_open fs/namei.c:3578 [inline]
 open_last_lookups fs/namei.c:3647 [inline]
 path_openat+0x1a9a/0x3470 fs/namei.c:3883
 do_filp_open+0x235/0x490 fs/namei.c:3913
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1442
 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: 0033:0x7ff80ad14019
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 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:00007ffcebdf6708 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ff80ad5d095 RCX: 00007ff80ad14019
RDX: 000000000000275a RSI: 0000000020000080 RDI: 00000000ffffff9c
RBP: 00007ff80ad8e5f0 R08: 00005555712cc4c0 R09: 00005555712cc4c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcebdf6730
R13: 00007ffcebdf6958 R14: 431bde82d7b634db R15: 00007ff80ad5d03b
 </TASK>
---[ end trace ]---


---
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