syzbot

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BUG: KCSAN: data-race in atime_needs_update / file_remove_privs

write to 0xffff8880988261bc of 4 bytes by task 10723 on cpu 0:
 inode_has_no_xattr include/linux/fs.h:3574 [inline]
 file_remove_privs+0x2e0/0x370 fs/inode.c:1943
 __generic_file_write_iter+0xda/0x330 mm/filemap.c:3393
 generic_file_write_iter+0x2f3/0x3e0 mm/filemap.c:3479
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x607/0x690 fs/read_write.c:578
 ksys_write+0xce/0x180 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write fs/read_write.c:640 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:640
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880988261bc of 4 bytes by task 10731 on cpu 1:
 atime_needs_update+0x29/0x370 fs/inode.c:1792
 touch_atime+0x53/0x1a0 fs/inode.c:1828
 file_accessed include/linux/fs.h:2229 [inline]
 shmem_file_read_iter+0x62e/0x720 mm/shmem.c:2604
 call_read_iter include/linux/fs.h:1902 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:312
 do_splice_to fs/splice.c:870 [inline]
 splice_direct_to_actor+0x2a8/0x660 fs/splice.c:950
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x562/0xb10 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1595 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1587
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10731 Comm: syz-executor.4 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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