syzbot

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BUG: KCSAN: data-race in generic_fillattr / setattr_copy

write to 0xffff8881055e8f7c of 4 bytes by task 3587 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1658 [inline]
 setattr_copy+0x2de/0x4a0 fs/attr.c:353
 shmem_setattr+0x5b4/0x7c0 mm/shmem.c:1357
 notify_change+0x872/0x8f0 fs/attr.c:546
 vfs_utimes+0x2fc/0x410 fs/utimes.c:66
 do_utimes_path fs/utimes.c:100 [inline]
 do_utimes+0x154/0x210 fs/utimes.c:141
 __do_sys_utimensat fs/utimes.c:160 [inline]
 __se_sys_utimensat fs/utimes.c:144 [inline]
 __x64_sys_utimensat+0xc4/0x170 fs/utimes.c:144
 x64_sys_call+0x278c/0x3000 arch/x86/include/generated/asm/syscalls_64.h:281
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881055e8f7c of 4 bytes by task 3586 on cpu 0:
 inode_get_mtime_nsec include/linux/fs.h:1644 [inline]
 inode_get_mtime include/linux/fs.h:1650 [inline]
 generic_fillattr+0x20e/0x340 fs/stat.c:102
 shmem_getattr+0x181/0x200 mm/shmem.c:1274
 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+0x111f/0x3000 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x17013fc1 -> 0x28e2e2c3

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3586 Comm: udevd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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