Attachment 198411 Details for Bug 294811 – test case to reproduce issue

test case to reproduce issue

main.c (text/x-csrc), 1.38 KB, created by Ian Campbell on 2007-09-18 14:33:57 UTC

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Creator: Ian Campbell

Created: 2007-09-18 14:33:57 UTC

Size: 1.38 KB

patch

obsolete

>#include <errno.h>
>#include <fcntl.h>
>#include <stdio.h>
>#include <string.h>
>#include <unistd.h>
>
>#include <sys/mman.h>
>#include <sys/stat.h>
>#include <sys/types.h>
>
>#define DEVICE "/dev/zero"
>#define REGION_SIZE 16*1024*1024
>
>int main(void)
>{
>	int fd;
>	void *mem, *lastmem = NULL;
>
>	fd = open(DEVICE, O_RDONLY);
>	if ( fd == -1 )
>	{
>		fprintf(stderr, "failed to open " DEVICE ": %s\n", strerror(errno));
>		return 1;
>	}
>
>	while (1)
>	{
>		mem = mmap(0, REGION_SIZE, PROT_READ, MAP_PRIVATE, fd, 0);
>		if ( mem == MAP_FAILED )
>		{
>			fprintf(stderr, "failed to mmap region: %s\n", strerror(errno));
>			return 1;
>		}
>
>		if ( mprotect(mem, REGION_SIZE, PROT_NONE) < 0 )
>		{
>			fprintf(stderr, "failed to mprotect region: %s\n", strerror(errno));
>			return 1;
>		}
>		printf("mapped PROT_NONE region at %p.\n", mem);
>
>		/*
>                 * Unmap previous region after mapping the next so
>                 * there is always at least one PROT_NONE region
>                 * mapped.
>                 *
>                 * If the kernel does not correctly handle non-present
>                 * PTEs then it will crash on unmap.
>                 */
>		if ( lastmem != NULL )
>		{
>			if ( munmap(lastmem, REGION_SIZE) < 0 )
>			{
>				fprintf(stderr, "failed to unmap region: %s\n", strerror(errno));
>				return 1;
>			}
>
>			printf("unmapped PROT_NONE region at %p.\n", lastmem);
>		}
>
>		lastmem = mem;
>
>		sleep(1);
>	}
>
>	return 0;
>}

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