[v6.1] UBSAN: shift-out-of-bounds in dbSplit (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6ae7ac5c4251 Linux 6.1.130
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14e29fa0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=8f36c2ade7921168
dashboard link: https://syzkaller.appspot.com/bug?extid=770402b99e245985119d
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=12e29fa0580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13c80654580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/004b2c8ffacc/disk-6ae7ac5c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/31d3704ef159/vmlinux-6ae7ac5c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3398729ada66/bzImage-6ae7ac5c.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/fe14617bdfb9/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=12764664580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+770402...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
================================================================================
UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:2644:11
shift exponent 121 is too large for 32-bit type 'int'
CPU: 0 PID: 4245 Comm: syz-executor460 Not tainted 6.1.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:151 [inline]
__ubsan_handle_shift_out_of_bounds+0x3bf/0x420 lib/ubsan.c:321
dbSplit+0x21a/0x220 fs/jfs/jfs_dmap.c:2644
dbAllocBits+0x4e0/0x9f0 fs/jfs/jfs_dmap.c:2196
dbAllocDmap fs/jfs/jfs_dmap.c:2037 [inline]
dbAllocDmapLev+0x24c/0x490 fs/jfs/jfs_dmap.c:1991
dbAllocCtl+0x147/0x9a0 fs/jfs/jfs_dmap.c:1828
dbAllocAG+0x28b/0x10b0 fs/jfs/jfs_dmap.c:1364
dbAlloc+0x654/0xc90 fs/jfs/jfs_dmap.c:888
dtSplitUp fs/jfs/jfs_dtree.c:981 [inline]
dtInsert+0xd76/0x6c80 fs/jfs/jfs_dtree.c:870
jfs_create+0x7b2/0xbb0 fs/jfs/namei.c:137
lookup_open fs/namei.c:3482 [inline]
open_last_lookups fs/namei.c:3550 [inline]
path_openat+0x12f1/0x2e60 fs/namei.c:3780
do_filp_open+0x230/0x480 fs/namei.c:3810
do_sys_openat2+0x13b/0x4f0 fs/open.c:1318
do_sys_open fs/open.c:1334 [inline]
__do_sys_open fs/open.c:1342 [inline]
__se_sys_open fs/open.c:1338 [inline]
__x64_sys_open+0x221/0x270 fs/open.c:1338
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7faea8b329b9
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:00007fffa733f838 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 633d73726f727265 RCX: 00007faea8b329b9
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000400000000400
RBP: 00007faea8bab610 R08: 00000000000060cc R09: 0000000000000000
R10: 00007fffa733f700 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffa733fa08 R14: 0000000000000001 R15: 0000000000000001
</TASK>
================================================================================


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