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BUG: KCSAN: data-race in generic_fillattr / inode_update_time

write to 0xffff88810186d10c of 4 bytes by task 14596 on cpu 0:
 inode_set_mtime_to_ts include/linux/fs.h:1660 [inline]
 inode_update_cmtime fs/inode.c:2133 [inline]
 inode_update_time+0x2cc/0x360 fs/inode.c:2158
 generic_update_time fs/inode.c:2189 [inline]
 file_update_time_flags+0x277/0x2e0 fs/inode.c:2422
 file_update_time+0x17/0x20 fs/inode.c:2443
 blkdev_write_iter+0x32e/0x4b0 block/fops.c:785
 iter_file_splice_write+0x6c4/0xa80 fs/splice.c:736
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x156/0x2a0 fs/splice.c:1159
 splice_direct_to_actor+0x311/0x670 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x382/0x650 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1419
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810186d10c of 4 bytes by task 5764 on cpu 1:
 inode_get_mtime_nsec include/linux/fs.h:1646 [inline]
 inode_get_mtime include/linux/fs.h:1652 [inline]
 generic_fillattr+0x20e/0x340 fs/stat.c:102
 shmem_getattr+0x181/0x200 mm/shmem.c:1302
 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x07730b21 -> 0x080089a2

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5764 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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