[syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbAlloc (2)

[syzbot <syzbot+debee9ab7ae2b34b0307@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    aed8aee11130 Merge tag 'pmdomain-v6.6-rc1' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14eb20c4680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f4894cf58531f
dashboard link: https://syzkaller.appspot.com/bug?extid=debee9ab7ae2b34b0307
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1e8c59eb8bd1/disk-aed8aee1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/edab4b80fc33/vmlinux-aed8aee1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0b280af46d8f/bzImage-aed8aee1.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+debee9ab7ae2b34b0307@syzkaller.appspotmail.com

loop3: detected capacity change from 0 to 32768
================================================================================
UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:799:12
shift exponent -16777216 is negative
CPU: 1 PID: 16087 Comm: syz-executor.3 Not tainted 6.6.0-rc1-syzkaller-00072-gaed8aee11130 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x125/0x1b0 lib/dump_stack.c:106
 ubsan_epilogue lib/ubsan.c:217 [inline]
 __ubsan_handle_shift_out_of_bounds+0x27a/0x600 lib/ubsan.c:387
 dbAlloc.cold+0x33/0x38 fs/jfs/jfs_dmap.c:799
 diNewExt+0x736/0x1a70 fs/jfs/jfs_imap.c:2252
 diAllocExt fs/jfs/jfs_imap.c:1946 [inline]
 diAllocAG+0x1707/0x2330 fs/jfs/jfs_imap.c:1663
 diAlloc+0x893/0x1a00 fs/jfs/jfs_imap.c:1584
 ialloc+0x8e/0xa70 fs/jfs/jfs_inode.c:56
 jfs_mkdir+0x240/0xb00 fs/jfs/namei.c:225
 vfs_mkdir+0x532/0x7e0 fs/namei.c:4120
 do_mkdirat+0x2a9/0x330 fs/namei.c:4143
 __do_sys_mkdirat fs/namei.c:4158 [inline]
 __se_sys_mkdirat fs/namei.c:4156 [inline]
 __x64_sys_mkdirat+0x115/0x170 fs/namei.c:4156
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fe9b047b5e7
Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe9b124eee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe9b047b5e7
RDX: 00000000000001ff RSI: 00000000200016c0 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000200016c0
R13: 00007fe9b124ef40 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
================================================================================


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