[syzbot] [exfat?] UBSAN: shift-out-of-bounds in exfat_fill_super (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9bacdd8996c7 Merge tag 'for-6.7-rc1-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12051eff680000
kernel config: https://syzkaller.appspot.com/x/.config?x=af04b7c4d36966d8
dashboard link: https://syzkaller.appspot.com/bug?extid=d33808a177641a02213e
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/cf19f53338f0/disk-9bacdd89.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dd19b4c3f5a9/vmlinux-9bacdd89.xz
kernel image: https://storage.googleapis.com/syzbot-assets/227655c91334/bzImage-9bacdd89.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d33808...@syzkaller.appspotmail.com

UBSAN: shift-out-of-bounds in fs/exfat/super.c:503:32
shift exponent 97 is too large for 64-bit type 'long long unsigned int'
CPU: 1 PID: 11990 Comm: syz-executor.2 Not tainted 6.7.0-rc1-syzkaller-00012-g9bacdd8996c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
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+0x2a6/0x480 lib/ubsan.c:387
exfat_read_boot_sector fs/exfat/super.c:503 [inline]
__exfat_fill_super fs/exfat/super.c:582 [inline]
exfat_fill_super.cold+0x119/0x12a fs/exfat/super.c:646
get_tree_bdev+0x3b5/0x650 fs/super.c:1598
vfs_get_tree+0x8c/0x370 fs/super.c:1771
do_new_mount fs/namespace.c:3337 [inline]
path_mount+0x1492/0x1ed0 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount fs/namespace.c:3863 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:3863
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f057367e1ea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 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:00007f05743c0ee8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f05743c0f80 RCX: 00007f057367e1ea
RDX: 00000000200001c0 RSI: 0000000020000a00 RDI: 00007f05743c0f40
RBP: 00000000200001c0 R08: 00007f05743c0f80 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000202 R12: 0000000020000a00
R13: 00007f05743c0f40 R14: 00000000000014e6 R15: 0000000020000240
</TASK>
================================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.