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BUG: KCSAN: data-race in fill_mg_cmtime / shmem_unlink

write to 0xffff8881058760ec of 4 bytes by task 3302 on cpu 0:
 inode_set_mtime_to_ts include/linux/fs.h:1839 [inline]
 shmem_unlink+0x13c/0x170 mm/shmem.c:3974
 vfs_unlink+0x26c/0x420 fs/namei.c:4673
 do_unlinkat+0x24e/0x480 fs/namei.c:4737
 __do_sys_unlink fs/namei.c:4783 [inline]
 __se_sys_unlink fs/namei.c:4781 [inline]
 __x64_sys_unlink+0x2e/0x40 fs/namei.c:4781
 x64_sys_call+0x2dcf/0x3000 arch/x86/include/generated/asm/syscalls_64.h:88
 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

read to 0xffff8881058760ec of 4 bytes by task 3507 on cpu 1:
 inode_get_mtime_nsec include/linux/fs.h:1825 [inline]
 inode_get_mtime include/linux/fs.h:1831 [inline]
 fill_mg_cmtime+0x5b/0x260 fs/stat.c:55
 generic_fillattr+0x24a/0x340 fs/stat.c:99
 shmem_getattr+0x181/0x200 mm/shmem.c:1257
 vfs_getattr_nosec+0x146/0x1e0 fs/stat.c:213
 vfs_getattr fs/stat.c:262 [inline]
 vfs_statx_path fs/stat.c:299 [inline]
 vfs_statx+0x113/0x390 fs/stat.c:356
 vfs_fstatat+0x115/0x170 fs/stat.c:375
 __do_sys_newfstatat fs/stat.c:542 [inline]
 __se_sys_newfstatat+0x55/0x260 fs/stat.c:536
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:536
 x64_sys_call+0x135a/0x3000 arch/x86/include/generated/asm/syscalls_64.h:263
 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: 0x231c47c3 -> 0x2340bdb9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3507 Comm: udevd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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