Commit 91cbacc3 authored by Michael Ellerman's avatar Michael Ellerman Committed by Linus Torvalds
Browse files

tools/testing/selftests/vm/map_fixed_noreplace.c: add test for MAP_FIXED_NOREPLACE 

Add a test for MAP_FIXED_NOREPLACE, based on some code originally by Jann
Horn.  This would have caught the overlap bug reported by Daniel Micay.

I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but
instead of writing a selftest I spent my time bike-shedding whether it
should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW ..  mea culpa.

Link: http://lkml.kernel.org/r/20181013133929.28653-1-mpe@ellerman.id.au


Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarKhalid Aziz <khalid.aziz@oracle.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Jann Horn <jannh@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jason Evans <jasone@google.com>
Cc: David Goldblatt <davidtgoldblatt@gmail.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7eef5f97

tools/testing/selftests/vm/.gitignore

+1 −0
Original line number Diff line number Diff line
@@ -13,3 +13,4 @@ mlock-random-test 
virtual_address_range

gup_benchmark

va_128TBswitch

map_fixed_noreplace

tools/testing/selftests/vm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark 
TEST_GEN_FILES += hugepage-mmap

TEST_GEN_FILES += hugepage-shm

TEST_GEN_FILES += map_hugetlb

TEST_GEN_FILES += map_fixed_noreplace

TEST_GEN_FILES += map_populate

TEST_GEN_FILES += mlock-random-test

TEST_GEN_FILES += mlock2-tests

tools/testing/selftests/vm/map_fixed_noreplace.c

0 → 100644
+206 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



/*

 * Test that MAP_FIXED_NOREPLACE works.

 *

 * Copyright 2018, Jann Horn <jannh@google.com>

 * Copyright 2018, Michael Ellerman, IBM Corporation.

 */



#include <sys/mman.h>

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>



#ifndef MAP_FIXED_NOREPLACE

#define MAP_FIXED_NOREPLACE 0x100000

#endif



#define BASE_ADDRESS	(256ul * 1024 * 1024)





static void dump_maps(void)

{

	char cmd[32];



	snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid());

	system(cmd);

}



int main(void)

{

	unsigned long flags, addr, size, page_size;

	char *p;



	page_size = sysconf(_SC_PAGE_SIZE);



	flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE;



	// Check we can map all the areas we need below

	errno = 0;

	addr = BASE_ADDRESS;

	size = 5 * page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);



	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p == MAP_FAILED) {

		dump_maps();

		printf("Error: couldn't map the space we need for the test\n");

		return 1;

	}



	errno = 0;

	if (munmap((void *)addr, 5 * page_size) != 0) {

		dump_maps();

		printf("Error: munmap failed!?\n");

		return 1;

	}

	printf("unmap() successful\n");



	errno = 0;

	addr = BASE_ADDRESS + page_size;

	size = 3 * page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p == MAP_FAILED) {

		dump_maps();

		printf("Error: first mmap() failed unexpectedly\n");

		return 1;

	}



	/*

	 * Exact same mapping again:

	 *   base |  free  | new

	 *     +1 | mapped | new

	 *     +2 | mapped | new

	 *     +3 | mapped | new

	 *     +4 |  free  | new

	 */

	errno = 0;

	addr = BASE_ADDRESS;

	size = 5 * page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p != MAP_FAILED) {

		dump_maps();

		printf("Error:1: mmap() succeeded when it shouldn't have\n");

		return 1;

	}



	/*

	 * Second mapping contained within first:

	 *

	 *   base |  free  |

	 *     +1 | mapped |

	 *     +2 | mapped | new

	 *     +3 | mapped |

	 *     +4 |  free  |

	 */

	errno = 0;

	addr = BASE_ADDRESS + (2 * page_size);

	size = page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p != MAP_FAILED) {

		dump_maps();

		printf("Error:2: mmap() succeeded when it shouldn't have\n");

		return 1;

	}



	/*

	 * Overlap end of existing mapping:

	 *   base |  free  |

	 *     +1 | mapped |

	 *     +2 | mapped |

	 *     +3 | mapped | new

	 *     +4 |  free  | new

	 */

	errno = 0;

	addr = BASE_ADDRESS + (3 * page_size);

	size = 2 * page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p != MAP_FAILED) {

		dump_maps();

		printf("Error:3: mmap() succeeded when it shouldn't have\n");

		return 1;

	}



	/*

	 * Overlap start of existing mapping:

	 *   base |  free  | new

	 *     +1 | mapped | new

	 *     +2 | mapped |

	 *     +3 | mapped |

	 *     +4 |  free  |

	 */

	errno = 0;

	addr = BASE_ADDRESS;

	size = 2 * page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p != MAP_FAILED) {

		dump_maps();

		printf("Error:4: mmap() succeeded when it shouldn't have\n");

		return 1;

	}



	/*

	 * Adjacent to start of existing mapping:

	 *   base |  free  | new

	 *     +1 | mapped |

	 *     +2 | mapped |

	 *     +3 | mapped |

	 *     +4 |  free  |

	 */

	errno = 0;

	addr = BASE_ADDRESS;

	size = page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p == MAP_FAILED) {

		dump_maps();

		printf("Error:5: mmap() failed when it shouldn't have\n");

		return 1;

	}



	/*

	 * Adjacent to end of existing mapping:

	 *   base |  free  |

	 *     +1 | mapped |

	 *     +2 | mapped |

	 *     +3 | mapped |

	 *     +4 |  free  |  new

	 */

	errno = 0;

	addr = BASE_ADDRESS + (4 * page_size);

	size = page_size;

	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);



	if (p == MAP_FAILED) {

		dump_maps();

		printf("Error:6: mmap() failed when it shouldn't have\n");

		return 1;

	}



	addr = BASE_ADDRESS;

	size = 5 * page_size;

	if (munmap((void *)addr, size) != 0) {

		dump_maps();

		printf("Error: munmap failed!?\n");

		return 1;

	}

	printf("unmap() successful\n");



	printf("OK\n");

	return 0;

}

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