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BUG: KCSAN: data-race in atime_needs_update / inode_update_timestamps

write to 0xffff8881069bb858 of 8 bytes by task 26223 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1594 [inline]
 inode_update_timestamps+0x16f/0x280 fs/inode.c:1865
 generic_update_time fs/inode.c:1900 [inline]
 inode_update_time fs/inode.c:1920 [inline]
 __file_update_time fs/inode.c:2109 [inline]
 file_modified_flags+0x2a7/0x340 fs/inode.c:2180
 file_modified+0x17/0x20 fs/inode.c:2196
 ext4_write_checks fs/ext4/file.c:279 [inline]
 ext4_buffered_write_iter+0x1d8/0x380 fs/ext4/file.c:295
 ext4_file_write_iter+0x29f/0xe30
 call_write_iter include/linux/fs.h:2108 [inline]
 iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3b9/0x970 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff8881069bb858 of 8 bytes by task 26224 on cpu 0:
 inode_get_mtime include/linux/fs.h:1588 [inline]
 relatime_need_update fs/inode.c:1814 [inline]
 atime_needs_update+0x2d2/0x3f0 fs/inode.c:1960
 touch_atime+0x4a/0x350 fs/inode.c:1975
 file_accessed include/linux/fs.h:2457 [inline]
 ext4_dio_read_iter fs/ext4/file.c:97 [inline]
 ext4_file_read_iter+0x275/0x2a0 fs/ext4/file.c:145
 call_read_iter include/linux/fs.h:2102 [inline]
 copy_splice_read+0x3a4/0x5d0 fs/splice.c:365
 do_splice_read fs/splice.c:984 [inline]
 splice_direct_to_actor+0x28e/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3b9/0x970 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x0000000036123efe -> 0x0000000036aad57e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26224 Comm: syz-executor.2 Tainted: G        W          6.8.0-syzkaller-11743-ga4145ce1e7bc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
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