[syzbot] UBSAN: shift-out-of-bounds in jfs_statfs

[syzbot <syzbot+3424c9550a49659f1704@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    247f34f7b803 Linux 6.1-rc2
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11904f2c880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1d3548a4365ba17d
dashboard link: https://syzkaller.appspot.com/bug?extid=3424c9550a49659f1704
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a5f39164dea4/disk-247f34f7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8d1b92f5a01f/vmlinux-247f34f7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3424c9550a49659f1704@syzkaller.appspotmail.com

================================================================================
UBSAN: shift-out-of-bounds in fs/jfs/super.c:140:14
shift exponent -236023038 is negative
CPU: 0 PID: 3985 Comm: syz-executor.4 Not tainted 6.1.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:151 [inline]
 __ubsan_handle_shift_out_of_bounds+0x33d/0x3b0 lib/ubsan.c:322
 jfs_statfs+0x503/0x510 fs/jfs/super.c:140
 statfs_by_dentry fs/statfs.c:66 [inline]
 vfs_statfs+0x136/0x310 fs/statfs.c:90
 user_statfs fs/statfs.c:105 [inline]
 __do_sys_statfs fs/statfs.c:195 [inline]
 __se_sys_statfs fs/statfs.c:192 [inline]
 __x64_sys_statfs+0x120/0x230 fs/statfs.c:192
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f96a5a8b5f9
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f96a6bce168 EFLAGS: 00000246 ORIG_RAX: 0000000000000089
RAX: ffffffffffffffda RBX: 00007f96a5babf80 RCX: 00007f96a5a8b5f9
RDX: 0000000000000000 RSI: 0000000020005380 RDI: 0000000020005340
RBP: 00007f96a5ae67b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff54f044bf R14: 00007f96a6bce300 R15: 0000000000022000
 </TASK>
================================================================================


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