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BUG: KCSAN: data-race in drop_nlink / generic_fillattr

write to 0xffff88810d0ba978 of 4 bytes by task 3304 on cpu 1:
 drop_nlink+0x3d/0xa0 fs/inode.c:418
 __simple_unlink fs/libfs.c:792 [inline]
 simple_unlink+0x60/0x80 fs/libfs.c:806
 shmem_unlink+0x12d/0x140 mm/shmem.c:4019
 shmem_rename2+0x18e/0x310 mm/shmem.c:4100
 vfs_rename+0xa9e/0xbf0 fs/namei.c:5938
 do_renameat2+0x39a/0x850 fs/namei.c:6056
 __do_sys_rename fs/namei.c:6099 [inline]
 __se_sys_rename fs/namei.c:6097 [inline]
 __x64_sys_rename+0x58/0x70 fs/namei.c:6097
 x64_sys_call+0x24e/0x3000 arch/x86/include/generated/asm/syscalls_64.h:83
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810d0ba978 of 4 bytes by task 3783 on cpu 0:
 generic_fillattr+0xfb/0x340 fs/stat.c:91
 shmem_getattr+0x181/0x200 mm/shmem.c:1302
 vfs_getattr_nosec+0x146/0x1e0 fs/stat.c:213
 vfs_getattr fs/stat.c:262 [inline]
 vfs_fstat fs/stat.c:281 [inline]
 __do_sys_newfstat fs/stat.c:555 [inline]
 __se_sys_newfstat+0x96/0x460 fs/stat.c:550
 __x64_sys_newfstat+0x31/0x40 fs/stat.c:550
 x64_sys_call+0x2c51/0x3000 arch/x86/include/generated/asm/syscalls_64.h:6
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3783 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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