syzbot

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BUG: KCSAN: data-race in sock_alloc_send_pskb / unix_shutdown

write to 0xffff8881248f2a6a of 1 bytes by task 12068 on cpu 0:
 unix_shutdown+0x78/0x350 net/unix/af_unix.c:2523
 __sys_shutdown net/socket.c:2203 [inline]
 __do_sys_shutdown net/socket.c:2211 [inline]
 __se_sys_shutdown+0xf2/0x140 net/socket.c:2209
 __x64_sys_shutdown+0x2d/0x40 net/socket.c:2209
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881248f2a6a of 1 bytes by task 12058 on cpu 1:
 sock_alloc_send_pskb+0x105/0x470 net/core/sock.c:2341
 unix_dgram_sendmsg+0x48a/0x1500 net/unix/af_unix.c:1679
 unix_seqpacket_sendmsg+0xc2/0x100 net/unix/af_unix.c:2063
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmmsg+0x322/0x4b0 net/socket.c:2496
 __do_sys_sendmmsg net/socket.c:2525 [inline]
 __se_sys_sendmmsg net/socket.c:2522 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2522
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12058 Comm: syz-executor.5 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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