[moderation] [fs?] KCSAN: data-race in fill_mg_cmtime / simple_rename_timestamp

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d6ef8b40d075 Merge tag 'sound-6.13-rc5' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1325dadf980000
kernel config: https://syzkaller.appspot.com/x/.config?x=87d3cfca6847d1fa
dashboard link: https://syzkaller.appspot.com/bug?extid=470427272fce68efeddf
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/435286475af8/disk-d6ef8b40.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8cede77e2455/vmlinux-d6ef8b40.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cc26cf1f072d/bzImage-d6ef8b40.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+470427...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in fill_mg_cmtime / simple_rename_timestamp

write to 0xffff888102591b1c of 4 bytes by task 11191 on cpu 0:
inode_set_mtime_to_ts include/linux/fs.h:1648 [inline]
simple_rename_timestamp+0x50/0xd0 fs/libfs.c:816
shmem_rename2+0x284/0x2c0 mm/shmem.c:3906
vfs_rename+0x875/0x9c0 fs/namei.c:5067
do_renameat2+0x6a2/0xa70 fs/namei.c:5224
__do_sys_rename fs/namei.c:5271 [inline]
__se_sys_rename fs/namei.c:5269 [inline]
__x64_sys_rename+0x58/0x70 fs/namei.c:5269
x64_sys_call+0x2b1c/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:83
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888102591b1c of 4 bytes by task 3602 on cpu 1:
inode_get_mtime_nsec include/linux/fs.h:1634 [inline]
inode_get_mtime include/linux/fs.h:1640 [inline]
fill_mg_cmtime+0x58/0x280 fs/stat.c:55
generic_fillattr+0x241/0x330 fs/stat.c:99
shmem_getattr+0x17b/0x200 mm/shmem.c:1181
vfs_getattr_nosec fs/stat.c:208 [inline]
vfs_getattr fs/stat.c:246 [inline]
vfs_statx_path+0x171/0x2d0 fs/stat.c:283
vfs_statx+0xe1/0x170 fs/stat.c:347
vfs_fstatat fs/stat.c:366 [inline]
__do_sys_newfstatat fs/stat.c:530 [inline]
__se_sys_newfstatat+0xdc/0x300 fs/stat.c:524
__x64_sys_newfstatat+0x55/0x70 fs/stat.c:524
x64_sys_call+0x236d/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:263
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x109581f2 -> 0x10cf6b4f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3602 Comm: udevd Not tainted 6.13.0-rc4-syzkaller-00054-gd6ef8b40d075 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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