/*
 * In the split VM code in 2.6.25-rc3-mm1 and later, we see PG_mlock
 * pages freed from the exit/exit_mmap path.  This test case creates
 * a process, forks it, mlocks, touches some memory and exits, to
 * try and trigger the bug - Rik van Riel, Mar 2008
 */
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

#define NUMFORKS 1
#define MEMSIZE 1024*1024

void child(void)
{
	char * mem;
	int i;

	mem = malloc(MEMSIZE);
	if (!mem) {
		printf("child could not allocate memory\n");
		exit(2);
	}

	/* Touch the memory so the kernel allocates actual pages. */
	for (i = 0; i < MEMSIZE; i++)
		mem[i] = i;

	/* This is where we can trigger the oops. */
	exit(0);
}

int main(int argc, char *argv)
{
	int i;
	int status;
	pid_t pid;
	int err;

	err = mlockall(MCL_CURRENT|MCL_FUTURE);
	if (err < 0) {
		printf("parent mlock failed\n");
		exit(1);
	}

	pid = getpid();

	printf("parent pid = %d\n", pid);

	for (i = 0; i < NUMFORKS ; i++) {
		pid = fork();

		if (!pid)	
			child(); /* does not return */
		else if (pid > 0)
			wait(&status);
		else {
			printf("fork failed\n");
			exit(1);
		}
	}
}