[moderation] [kernfs?] KCSAN: data-race in inode_set_ctime_to_ts / inode_set_ctime_to_ts (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 72761a7e3122 Merge tag 'driver-core-6.18-rc3' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13d21e7c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=15383e23338541bf
dashboard link: https://syzkaller.appspot.com/bug?extid=d7b0ca727977befe2b2d
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [gre...@linuxfoundation.org linux-...@vger.kernel.org t...@kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ab21b32e3385/disk-72761a7e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c1dde9668b38/vmlinux-72761a7e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2d9a7a942e42/bzImage-72761a7e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d7b0ca...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in inode_set_ctime_to_ts / inode_set_ctime_to_ts

write to 0xffff8881071f9888 of 4 bytes by task 3312 on cpu 1:
inode_set_ctime_to_ts+0x84/0x170 fs/inode.c:2715
set_inode_attr fs/kernfs/inode.c:165 [inline]
kernfs_refresh_inode fs/kernfs/inode.c:179 [inline]
kernfs_iop_permission+0x190/0x220 fs/kernfs/inode.c:290
do_inode_permission fs/namei.c:526 [inline]
inode_permission+0x1ca/0x310 fs/namei.c:593
may_create+0x196/0x1f0 fs/namei.c:3318
vfs_mkdir+0x5a/0x340 fs/namei.c:4436
do_mkdirat+0x132/0x3f0 fs/namei.c:4486
__do_sys_mkdirat fs/namei.c:4503 [inline]
__se_sys_mkdirat fs/namei.c:4501 [inline]
__x64_sys_mkdirat+0x4c/0x60 fs/namei.c:4501
x64_sys_call+0x2b7/0x3000 arch/x86/include/generated/asm/syscalls_64.h:259
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff8881071f9888 of 4 bytes by task 3315 on cpu 0:
inode_set_ctime_to_ts+0x84/0x170 fs/inode.c:2715
set_inode_attr fs/kernfs/inode.c:165 [inline]
kernfs_refresh_inode fs/kernfs/inode.c:179 [inline]
kernfs_iop_permission+0x190/0x220 fs/kernfs/inode.c:290
do_inode_permission fs/namei.c:526 [inline]
inode_permission+0x1ca/0x310 fs/namei.c:593
may_lookup fs/namei.c:1873 [inline]
link_path_walk+0x63c/0x900 fs/namei.c:2467
path_openat+0x1de/0x2170 fs/namei.c:4130
do_filp_open+0x109/0x230 fs/namei.c:4161
do_sys_openat2+0xa6/0x110 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0xf2/0x120 fs/open.c:1463
x64_sys_call+0x2eab/0x3000 arch/x86/include/generated/asm/syscalls_64.h:258
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x239f5c4a -> 0x2b53dccd

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3315 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
==================================================================


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