[syzbot] [exfat?] KMSAN: uninit-value in vfat_rename2

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    e7ed34365879 Merge tag 'mailbox-v6.12' of git://git.kernel..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11b54ea9980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=92da5062b0d65389
dashboard link: https://syzkaller.appspot.com/bug?extid=ef0d7bc412553291aa86
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=14b7ed07980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=101dfd9f980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/66cc3d8c5c10/disk-e7ed3436.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c7769a88b445/vmlinux-e7ed3436.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c1fe4c6ee436/bzImage-e7ed3436.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/2ab98c65fd49/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/7ffc0eb73060/mount_5.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ef0d7bc412553291aa86@xxxxxxxxxxxxxxxxxxxxxxxxx

Buffer I/O error on dev loop4, logical block 34, lost sync page write
FAT-fs (loop4): unable to read inode block for updating (i_pos 548)
=====================================================
BUG: KMSAN: uninit-value in vfat_rename fs/fat/namei_vfat.c:1038 [inline]
BUG: KMSAN: uninit-value in vfat_rename2+0x3dda/0x3de0 fs/fat/namei_vfat.c:1174
 vfat_rename fs/fat/namei_vfat.c:1038 [inline]
 vfat_rename2+0x3dda/0x3de0 fs/fat/namei_vfat.c:1174
 vfs_rename+0x1d9d/0x2280 fs/namei.c:5013
 do_renameat2+0x18cc/0x1d50 fs/namei.c:5170
 __do_sys_rename fs/namei.c:5217 [inline]
 __se_sys_rename fs/namei.c:5215 [inline]
 __x64_sys_rename+0xe8/0x140 fs/namei.c:5215
 x64_sys_call+0x1e4d/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:83
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable sinfo.i created at:
 vfat_rename fs/fat/namei_vfat.c:937 [inline]
 vfat_rename2+0x124/0x3de0 fs/fat/namei_vfat.c:1174
 vfs_rename+0x1d9d/0x2280 fs/namei.c:5013

CPU: 1 UID: 0 PID: 5211 Comm: syz-executor818 Not tainted 6.11.0-syzkaller-12113-ge7ed34365879 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================


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