Commit f6df89c3 authored by Wei Yang's avatar Wei Yang Committed by Mike Rapoport (IBM)
Browse files

memblock tests: add memblock_reserve_many_may_conflict_check() 



This may trigger the case fixed by commit 48c3b583 ("mm/memblock:
fix overlapping allocation when doubling reserved array").

This is done by adding the 129th reserve region into memblock.memory. If
memblock_double_array() use this reserve region as new array, it fails.

Signed-off-by: default avatarWei Yang <richard.weiyang@gmail.com>
Link: https://lore.kernel.org/r/20240507075833.6346-3-richard.weiyang@gmail.com


Signed-off-by: default avatarMike Rapoport (IBM) <rppt@kernel.org>
parent 3d316519

tools/testing/memblock/tests/basic_api.c

+151 −0
Original line number Diff line number Diff line
@@ -1088,6 +1088,156 @@ static int memblock_reserve_all_locations_check(void) 
	return 0;

}



/*

 * A test that trying to reserve the 129th memory block at all locations.

 * Expect to trigger memblock_double_array() to double the

 * memblock.memory.max, find a new valid memory as reserved.regions. And make

 * sure it doesn't conflict with the range we want to reserve.

 *

 * For example, we have 128 regions in reserved and now want to reserve

 * the skipped one. Since reserved is full, memblock_double_array() would find

 * an available range in memory for the new array. We intended to put two

 * ranges in memory with one is the exact range of the skipped one. Before

 * commit 48c3b583bbdd ("mm/memblock: fix overlapping allocation when doubling

 * reserved array"), the new array would sits in the skipped range which is a

 * conflict. The expected new array should be allocated from memory.regions[0].

 *

 *           0                               1

 * memory    +-------+                       +-------+

 *           |  32K  |                       |  32K  |

 *           +-------+ ------+-------+-------+-------+

 *                   |<-32K->|<-32K->|<-32K->|

 *

 *                           0               skipped           127

 * reserved                  +-------+       .........         +-------+

 *                           |  32K  |       .  32K  .   ...   |  32K  |

 *                           +-------+-------+-------+         +-------+

 *                                   |<-32K->|

 *                                           ^

 *                                           |

 *                                           |

 *                                           skipped one

 */

/* Keep the gap so these memory region will not be merged. */

#define MEMORY_BASE_OFFSET(idx, offset) ((offset) + (MEM_SIZE * 2) * (idx))

static int memblock_reserve_many_may_conflict_check(void)

{

	int i, skip;

	void *orig_region;

	struct region r = {

		.base = SZ_16K,

		.size = SZ_16K,

	};

	phys_addr_t new_reserved_regions_size;



	/*

	 *  0        1          129

	 *  +---+    +---+      +---+

	 *  |32K|    |32K|  ..  |32K|

	 *  +---+    +---+      +---+

	 *

	 * Pre-allocate the range for 129 memory block + one range for double

	 * memblock.reserved.regions at idx 0.

	 */

	dummy_physical_memory_init();

	phys_addr_t memory_base = dummy_physical_memory_base();

	phys_addr_t offset = PAGE_ALIGN(memory_base);



	PREFIX_PUSH();



	/* Reserve the 129th memory block for all possible positions*/

	for (skip = 1; skip <= INIT_MEMBLOCK_REGIONS + 1; skip++) {

		reset_memblock_regions();

		memblock_allow_resize();



		reset_memblock_attributes();

		/* Add a valid memory region used by double_array(). */

		memblock_add(MEMORY_BASE_OFFSET(0, offset), MEM_SIZE);

		/*

		 * Add a memory region which will be reserved as 129th memory

		 * region. This is not expected to be used by double_array().

		 */

		memblock_add(MEMORY_BASE_OFFSET(skip, offset), MEM_SIZE);



		for (i = 1; i <= INIT_MEMBLOCK_REGIONS + 1; i++) {

			if (i == skip)

				continue;



			/* Reserve some fakes memory region to fulfill the memblock. */

			memblock_reserve(MEMORY_BASE_OFFSET(i, offset), MEM_SIZE);



			if (i < skip) {

				ASSERT_EQ(memblock.reserved.cnt, i);

				ASSERT_EQ(memblock.reserved.total_size, i * MEM_SIZE);

			} else {

				ASSERT_EQ(memblock.reserved.cnt, i - 1);

				ASSERT_EQ(memblock.reserved.total_size, (i - 1) * MEM_SIZE);

			}

		}



		orig_region = memblock.reserved.regions;



		/* This reserve the 129 memory_region, and makes it double array. */

		memblock_reserve(MEMORY_BASE_OFFSET(skip, offset), MEM_SIZE);



		/*

		 * This is the memory region size used by the doubled reserved.regions,

		 * and it has been reserved due to it has been used. The size is used to

		 * calculate the total_size that the memblock.reserved have now.

		 */

		new_reserved_regions_size = PAGE_ALIGN((INIT_MEMBLOCK_REGIONS * 2) *

						sizeof(struct memblock_region));

		/*

		 * The double_array() will find a free memory region as the new

		 * reserved.regions, and the used memory region will be reserved, so

		 * there will be one more region exist in the reserved memblock. And the

		 * one more reserved region's size is new_reserved_regions_size.

		 */

		ASSERT_EQ(memblock.reserved.cnt, INIT_MEMBLOCK_REGIONS + 2);

		ASSERT_EQ(memblock.reserved.total_size, (INIT_MEMBLOCK_REGIONS + 1) * MEM_SIZE +

							new_reserved_regions_size);

		ASSERT_EQ(memblock.reserved.max, INIT_MEMBLOCK_REGIONS * 2);



		/*

		 * The first reserved region is allocated for double array

		 * with the size of new_reserved_regions_size and the base to be

		 * MEMORY_BASE_OFFSET(0, offset) + SZ_32K - new_reserved_regions_size

		 */

		ASSERT_EQ(memblock.reserved.regions[0].base + memblock.reserved.regions[0].size,

			  MEMORY_BASE_OFFSET(0, offset) + SZ_32K);

		ASSERT_EQ(memblock.reserved.regions[0].size, new_reserved_regions_size);



		/*

		 * Now memblock_double_array() works fine. Let's check after the

		 * double_array(), the memblock_reserve() still works as normal.

		 */

		memblock_reserve(r.base, r.size);

		ASSERT_EQ(memblock.reserved.regions[0].base, r.base);

		ASSERT_EQ(memblock.reserved.regions[0].size, r.size);



		ASSERT_EQ(memblock.reserved.cnt, INIT_MEMBLOCK_REGIONS + 3);

		ASSERT_EQ(memblock.reserved.total_size, (INIT_MEMBLOCK_REGIONS + 1) * MEM_SIZE +

							new_reserved_regions_size +

							r.size);

		ASSERT_EQ(memblock.reserved.max, INIT_MEMBLOCK_REGIONS * 2);



		/*

		 * The current reserved.regions is occupying a range of memory that

		 * allocated from dummy_physical_memory_init(). After free the memory,

		 * we must not use it. So restore the origin memory region to make sure

		 * the tests can run as normal and not affected by the double array.

		 */

		memblock.reserved.regions = orig_region;

		memblock.reserved.cnt = INIT_MEMBLOCK_RESERVED_REGIONS;

	}



	dummy_physical_memory_cleanup();



	test_pass_pop();



	return 0;

}



static int memblock_reserve_checks(void)

{

	prefix_reset();
@@ -1104,6 +1254,7 @@ static int memblock_reserve_checks(void) 
	memblock_reserve_near_max_check();

	memblock_reserve_many_check();

	memblock_reserve_all_locations_check();

	memblock_reserve_many_may_conflict_check();



	prefix_pop();

tools/testing/memblock/tests/common.c

+2 −2
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ void reset_memblock_attributes(void) 


static inline void fill_memblock(void)

{

	memset(memory_block.base, 1, MEM_SIZE);

	memset(memory_block.base, 1, PHYS_MEM_SIZE);

}



void setup_memblock(void)
@@ -103,7 +103,7 @@ void setup_numa_memblock(const unsigned int node_fracs[]) 


void dummy_physical_memory_init(void)

{

	memory_block.base = malloc(MEM_SIZE);

	memory_block.base = malloc(PHYS_MEM_SIZE);

	assert(memory_block.base);

	fill_memblock();

}

tools/testing/memblock/tests/common.h

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <../selftests/kselftest.h>



#define MEM_SIZE		SZ_32K

#define PHYS_MEM_SIZE		SZ_16M

#define NUMA_NODES		8



#define INIT_MEMBLOCK_REGIONS			128