[syzbot] [kernfs?] KMSAN: uninit-value in inode_set_ctime_to_ts

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cd7a5651db26 alpha: add missing address argument in call t..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1037415a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=50148b563a4d5941
dashboard link: https://syzkaller.appspot.com/bug?extid=e2fd93a2773af7f9ea51
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/23c623fcb1bf/disk-cd7a5651.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5128bb44f38d/vmlinux-cd7a5651.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a65d6b263e08/bzImage-cd7a5651.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e2fd93...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in inode_set_ctime_to_ts+0x1eb/0x3a0 fs/inode.c:2777
inode_set_ctime_to_ts+0x1eb/0x3a0 fs/inode.c:2777
inode_set_ctime_current+0x646/0x1690 fs/inode.c:2842
simple_inode_init_ts+0x43/0x180 fs/libfs.c:2133
set_default_inode_attr fs/kernfs/inode.c:155 [inline]
kernfs_init_inode fs/kernfs/inode.c:209 [inline]
kernfs_get_inode+0x23a/0xb60 fs/kernfs/inode.c:255
kernfs_iop_lookup+0x2ff/0x600 fs/kernfs/dir.c:1241
__lookup_slow+0x56a/0x770 fs/namei.c:1916
lookup_slow+0x6a/0xd0 fs/namei.c:1933
walk_component fs/namei.c:2279 [inline]
link_path_walk+0x170f/0x2650 fs/namei.c:2647
path_lookupat+0x107/0xdf0 fs/namei.c:2803
filename_lookup+0x2bc/0x800 fs/namei.c:2833
vfs_statx+0xcf/0x290 fs/stat.c:353
vfs_fstatat+0x2dc/0x400 fs/stat.c:373
__do_sys_newfstatat fs/stat.c:538 [inline]
__se_sys_newfstatat+0x64/0x870 fs/stat.c:532
__x64_sys_newfstatat+0xbd/0x120 fs/stat.c:532
x64_sys_call+0x3824/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:263
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
inode_set_ctime_to_ts+0x1e4/0x3a0 fs/inode.c:2777
inode_set_ctime_current+0x646/0x1690 fs/inode.c:2842
simple_inode_init_ts+0x43/0x180 fs/libfs.c:2133
set_default_inode_attr fs/kernfs/inode.c:155 [inline]
kernfs_init_inode fs/kernfs/inode.c:209 [inline]
kernfs_get_inode+0x23a/0xb60 fs/kernfs/inode.c:255
kernfs_iop_lookup+0x2ff/0x600 fs/kernfs/dir.c:1241
__lookup_slow+0x56a/0x770 fs/namei.c:1916
lookup_slow+0x6a/0xd0 fs/namei.c:1933
walk_component fs/namei.c:2279 [inline]
link_path_walk+0x170f/0x2650 fs/namei.c:2647
path_lookupat+0x107/0xdf0 fs/namei.c:2803
filename_lookup+0x2bc/0x800 fs/namei.c:2833
vfs_statx+0xcf/0x290 fs/stat.c:353
vfs_fstatat+0x2dc/0x400 fs/stat.c:373
__do_sys_newfstatat fs/stat.c:538 [inline]
__se_sys_newfstatat+0x64/0x870 fs/stat.c:532
__x64_sys_newfstatat+0xbd/0x120 fs/stat.c:532
x64_sys_call+0x3824/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:263
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
inode_set_ctime_to_ts+0x19f/0x3a0 fs/inode.c:-1
inode_set_ctime_current+0x646/0x1690 fs/inode.c:2842
simple_inode_init_ts+0x43/0x180 fs/libfs.c:2133
set_default_inode_attr fs/kernfs/inode.c:155 [inline]
kernfs_init_inode fs/kernfs/inode.c:209 [inline]
kernfs_get_inode+0x23a/0xb60 fs/kernfs/inode.c:255
kernfs_iop_lookup+0x2ff/0x600 fs/kernfs/dir.c:1241
__lookup_slow+0x56a/0x770 fs/namei.c:1916
lookup_slow+0x6a/0xd0 fs/namei.c:1933
walk_component fs/namei.c:2279 [inline]
link_path_walk+0x170f/0x2650 fs/namei.c:2647
path_lookupat+0x107/0xdf0 fs/namei.c:2803
filename_lookup+0x2bc/0x800 fs/namei.c:2833
vfs_statx+0xcf/0x290 fs/stat.c:353
vfs_fstatat+0x2dc/0x400 fs/stat.c:373
__do_sys_newfstatat fs/stat.c:538 [inline]
__se_sys_newfstatat+0x64/0x870 fs/stat.c:532
__x64_sys_newfstatat+0xbd/0x120 fs/stat.c:532
x64_sys_call+0x3824/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:263
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Local variable retval created at:
inode_set_ctime_current+0x3b/0x1690 fs/inode.c:2833
simple_inode_init_ts+0x43/0x180 fs/libfs.c:2133

CPU: 0 UID: 0 PID: 5142 Comm: udevadm Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
=====================================================


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