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BUG: KCSAN: data-race in fill_mg_cmtime / simple_rename_timestamp

write to 0xffff888103fcc664 of 4 bytes by task 3286 on cpu 0:
 inode_set_mtime_to_ts include/linux/fs.h:1655 [inline]
 simple_rename_timestamp+0x53/0xd0 fs/libfs.c:840
 shmem_rename2+0x2d5/0x310 mm/shmem.c:4020
 vfs_rename+0x963/0xac0 fs/namei.c:6074
 filename_renameat2+0x3a4/0x6a0 fs/namei.c:6192
 __do_sys_rename fs/namei.c:6236 [inline]
 __se_sys_rename+0x4a/0x1c0 fs/namei.c:6232
 __x64_sys_rename+0x31/0x40 fs/namei.c:6232
 x64_sys_call+0x2b3/0x3020 arch/x86/include/generated/asm/syscalls_64.h:83
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888103fcc664 of 4 bytes by task 6339 on cpu 1:
 inode_get_mtime_nsec include/linux/fs.h:1641 [inline]
 inode_get_mtime include/linux/fs.h:1647 [inline]
 fill_mg_cmtime+0x5b/0x240 fs/stat.c:55
 generic_fillattr+0x24d/0x340 fs/stat.c:99
 shmem_getattr+0x181/0x200 mm/shmem.c:1312
 vfs_getattr_nosec+0x146/0x1e0 fs/stat.c:213
 vfs_getattr+0x48/0x60 fs/stat.c:262
 vfs_statx_path+0x28/0x140 fs/stat.c:299
 vfs_statx+0xc4/0x170 fs/stat.c:356
 vfs_fstatat+0x118/0x170 fs/stat.c:373
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat+0x55/0x3e0 fs/stat.c:532
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:532
 x64_sys_call+0x2c64/0x3020 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x393a7ce2 -> 0x39534a63

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6339 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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