[syzbot] [overlayfs?] KMSAN: uninit-value in ovl_fileattr_get

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8fdb05de0e2d Merge tag 'net-6.19-rc9' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13d888aa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9682a42d8ec8b05c
dashboard link: https://syzkaller.appspot.com/bug?extid=fa79520cb6cf363d660d
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1233cb22580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1035878a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/25d060d68c51/disk-8fdb05de.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f033f4d0ec73/vmlinux-8fdb05de.xz
kernel image: https://storage.googleapis.com/syzbot-assets/942ea5e5d5f5/bzImage-8fdb05de.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fa7952...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in ovl_security_fileattr fs/overlayfs/inode.c:617 [inline]
BUG: KMSAN: uninit-value in ovl_real_fileattr_get fs/overlayfs/inode.c:701 [inline]
BUG: KMSAN: uninit-value in ovl_fileattr_get+0x5cd/0x650 fs/overlayfs/inode.c:720
ovl_security_fileattr fs/overlayfs/inode.c:617 [inline]
ovl_real_fileattr_get fs/overlayfs/inode.c:701 [inline]
ovl_fileattr_get+0x5cd/0x650 fs/overlayfs/inode.c:720
vfs_fileattr_get fs/file_attr.c:94 [inline]
__do_sys_file_getattr fs/file_attr.c:416 [inline]
__se_sys_file_getattr+0x6cb/0xbd0 fs/file_attr.c:372
__x64_sys_file_getattr+0xe4/0x150 fs/file_attr.c:372
x64_sys_call+0x17cd/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:469
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
ovl_security_fileattr fs/overlayfs/inode.c:612 [inline]
ovl_real_fileattr_get fs/overlayfs/inode.c:701 [inline]
ovl_fileattr_get+0x5c6/0x650 fs/overlayfs/inode.c:720
vfs_fileattr_get fs/file_attr.c:94 [inline]
__do_sys_file_getattr fs/file_attr.c:416 [inline]
__se_sys_file_getattr+0x6cb/0xbd0 fs/file_attr.c:372
__x64_sys_file_getattr+0xe4/0x150 fs/file_attr.c:372
x64_sys_call+0x17cd/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:469
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable fa.i created at:
__do_sys_file_getattr fs/file_attr.c:380 [inline]
__se_sys_file_getattr+0x8c/0xbd0 fs/file_attr.c:372
__x64_sys_file_getattr+0xe4/0x150 fs/file_attr.c:372

CPU: 0 UID: 0 PID: 6044 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
=====================================================


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