syzbot

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

write to 0xffff8881017a20ec of 4 bytes by task 3762 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1698 [inline]
 shmem_mknod+0x136/0x180 mm/shmem.c:3871
 shmem_create+0x34/0x40 mm/shmem.c:3930
 lookup_open fs/namei.c:3666 [inline]
 open_last_lookups fs/namei.c:3765 [inline]
 path_openat+0xec8/0x2000 fs/namei.c:4001
 do_filp_open+0x115/0x240 fs/namei.c:4031
 do_sys_openat2+0xaa/0x110 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_openat fs/open.c:1460 [inline]
 __se_sys_openat fs/open.c:1455 [inline]
 __x64_sys_openat+0xf8/0x120 fs/open.c:1455
 x64_sys_call+0x1ac/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881017a20ec of 4 bytes by task 3292 on cpu 0:
 inode_get_mtime_nsec include/linux/fs.h:1684 [inline]
 inode_get_mtime include/linux/fs.h:1690 [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:1249
 vfs_getattr_nosec fs/stat.c:208 [inline]
 vfs_getattr+0x172/0x1b0 fs/stat.c:246
 vfs_statx_path fs/stat.c:283 [inline]
 vfs_statx+0x12c/0x310 fs/stat.c:349
 vfs_fstatat+0xe4/0x130 fs/stat.c:368
 __do_sys_newfstatat fs/stat.c:532 [inline]
 __se_sys_newfstatat+0x58/0x260 fs/stat.c:526
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:526
 x64_sys_call+0x2d6f/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x19ff7698 -> 0x1a052408

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3292 Comm: udevd Not tainted 6.14.0-syzkaller-05877-g1a9239bb4253 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================