Re: [syzbot] [net?] WARNING in unreserve_psock

[David Howells <dhowells@redhat.com>]

Here's a reduced testcase.

David
---
// https://syzkaller.appspot.com/bug?id=6ffe7d1ebf1efaddb7ddd04784b9b22a8562b8d0
// autogenerated by syzkaller (https://github.com/google/syzkaller)
#define _GNU_SOURCE
#include <endian.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#include <linux/kcm.h>

#define OSERROR(R, S) do { if ((long)(R) == -1L) { perror((S)); exit(1); } } while(0)

int main(void)
{
	struct msghdr msg;
	int kcmfd, res;

	kcmfd = socket(AF_KCM, SOCK_DGRAM, KCMPROTO_CONNECTED);
	OSERROR(kcmfd, "socket");

	memset(&msg, 0, sizeof(msg));
	res = sendmsg(kcmfd, &msg, 0);
	OSERROR(res, "sendmsg");
	return 0;
}