syzbot

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BUG: KCSAN: data-race in unix_release_sock / unix_stream_sendpage

write to 0xffff8880996a366a of 1 bytes by task 24551 on cpu 0:
 unix_release_sock+0x25e/0x650 net/unix/af_unix.c:548
 unix_release+0x2f/0x50 net/unix/af_unix.c:861
 __sock_release net/socket.c:596 [inline]
 sock_close+0x6c/0x150 net/socket.c:1277
 __fput+0x246/0x4d0 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:165 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:192
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:267
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880996a366a of 1 bytes by task 24553 on cpu 1:
 unix_stream_sendpage+0x17c/0xa60 net/unix/af_unix.c:1961
 kernel_sendpage net/socket.c:3642 [inline]
 sock_sendpage+0x84/0xc0 net/socket.c:944
 pipe_to_sendpage+0x128/0x160 fs/splice.c:448
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x1f7/0x4f0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 generic_splice_sendpage+0x80/0xb0 fs/splice.c:834
 do_splice_from fs/splice.c:846 [inline]
 do_splice+0xaf4/0x10c0 fs/splice.c:1144
 __do_sys_splice fs/splice.c:1419 [inline]
 __se_sys_splice fs/splice.c:1401 [inline]
 __x64_sys_splice+0xf2/0x190 fs/splice.c:1401
 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: 24553 Comm: syz-executor.3 Not tainted 5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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