[moderation] [mm?] upstream test error: KCSAN: data-race in fill_mg_cmtime / shmem_unlink

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7eef7e306d3c Merge tag 'for-6.13/dm-changes' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=121f1530580000
kernel config: https://syzkaller.appspot.com/x/.config?x=db310a9aeec0c8cb
dashboard link: https://syzkaller.appspot.com/bug?extid=f955a9fb207e527f2313
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org hu...@google.com linux-...@vger.kernel.org linu...@kvack.org]

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/68f4c74b9423/disk-7eef7e30.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/762ca2152588/vmlinux-7eef7e30.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bb6c1c9bd36c/bzImage-7eef7e30.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f955a9...@syzkaller.appspotmail.com

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

write to 0xffff888104d4cc94 of 4 bytes by task 3933 on cpu 0:
inode_set_mtime_to_ts include/linux/fs.h:1648 [inline]
shmem_unlink+0x13b/0x170 mm/shmem.c:3803
vfs_unlink+0x275/0x430 fs/namei.c:4523
do_unlinkat+0x237/0x4d0 fs/namei.c:4587
__do_sys_unlink fs/namei.c:4635 [inline]
__se_sys_unlink fs/namei.c:4633 [inline]
__x64_sys_unlink+0x2e/0x40 fs/namei.c:4633
x64_sys_call+0x2329/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:88
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 0xffff888104d4cc94 of 4 bytes by task 3934 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:1177
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: 0x1be6e1bb -> 0x1bf9ab0c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3934 Comm: udevd Not tainted 6.12.0-syzkaller-09567-g7eef7e306d3c #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.