syzbot

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BUG: KCSAN: data-race in atime_needs_update / file_remove_privs

write to 0xffff888120c046dc of 4 bytes by task 4913 on cpu 0:
 inode_has_no_xattr include/linux/fs.h:3456 [inline]
 file_remove_privs+0x2e0/0x370 fs/inode.c:1943
 __generic_file_write_iter+0xda/0x330 mm/filemap.c:3576
 generic_file_write_iter+0x2f3/0x3e0 mm/filemap.c:3662
 call_write_iter include/linux/fs.h:1882 [inline]
 do_iter_readv_writev+0x32e/0x3d0 fs/read_write.c:713
 do_iter_write+0x112/0x4b0 fs/read_write.c:1018
 vfs_writev fs/read_write.c:1091 [inline]
 do_pwritev+0x1a4/0x2e0 fs/read_write.c:1188
 __do_sys_pwritev fs/read_write.c:1235 [inline]
 __se_sys_pwritev fs/read_write.c:1230 [inline]
 __x64_sys_pwritev+0x54/0x60 fs/read_write.c:1230
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888120c046dc of 4 bytes by task 4914 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:2206 [inline]
 splice_direct_to_actor+0x580/0x660 fs/splice.c:989
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x56a/0xba0 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4914 Comm: syz-executor.4 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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