syzbot

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BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg

write to 0xffff8881cc296b10 of 8 bytes by task 30398 on cpu 0:
 netlink_recvmsg+0xd5/0x750 net/netlink/af_netlink.c:1977
 ____sys_recvmsg+0x15d/0x310 include/linux/uio.h:240
 ___sys_recvmsg net/socket.c:2653 [inline]
 do_recvmmsg+0x35c/0x9f0 net/socket.c:2747
 __sys_recvmmsg net/socket.c:2828 [inline]
 __do_sys_recvmmsg net/socket.c:2849 [inline]
 __se_sys_recvmmsg net/socket.c:2842 [inline]
 __x64_sys_recvmmsg+0xe6/0x150 net/socket.c:2842
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881cc296b10 of 8 bytes by task 30411 on cpu 1:
 netlink_recvmsg+0x8d/0x750 net/netlink/af_netlink.c:1976
 sock_recvmsg_nosec net/socket.c:943 [inline]
 sock_recvmsg net/socket.c:961 [inline]
 __sys_recvfrom+0x1d7/0x2a0 net/socket.c:2076
 __do_sys_recvfrom net/socket.c:2094 [inline]
 __se_sys_recvfrom net/socket.c:2090 [inline]
 __x64_sys_recvfrom+0x74/0x90 net/socket.c:2090
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000000 -> 0x000000000000027f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30411 Comm: syz-executor.1 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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