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BUG: KCSAN: data-race in atime_needs_update / inode_update_timestamps

write to 0xffff88811b8b82dc of 4 bytes by task 10767 on cpu 0:
 inode_set_mtime_to_ts include/linux/fs.h:1658 [inline]
 inode_update_timestamps+0x147/0x270 fs/inode.c:2116
 generic_update_time fs/inode.c:2151 [inline]
 inode_update_time fs/inode.c:2171 [inline]
 file_update_time_flags+0x269/0x300 fs/inode.c:2398
 file_update_time+0x17/0x20 fs/inode.c:2419
 __generic_file_write_iter+0x4e/0x120 mm/filemap.c:4412
 generic_file_write_iter+0x8d/0x310 mm/filemap.c:4457
 iter_file_splice_write+0x6bc/0xa80 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x156/0x2a0 fs/splice.c:1161
 splice_direct_to_actor+0x311/0x670 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 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 0xffff88811b8b82dc of 4 bytes by task 10772 on cpu 1:
 inode_get_mtime_nsec include/linux/fs.h:1644 [inline]
 inode_get_mtime include/linux/fs.h:1650 [inline]
 relatime_need_update fs/inode.c:2065 [inline]
 atime_needs_update+0x2a8/0x3e0 fs/inode.c:2211
 touch_atime+0x4a/0x340 fs/inode.c:2226
 file_accessed include/linux/fs.h:2254 [inline]
 filemap_splice_read+0x6f1/0x780 mm/filemap.c:3135
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26e/0x670 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0x202fc027 -> 0x20c856a7

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 10772 Comm: syz.3.2126 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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