diff --git a/storage/innobase/buf/buf0lru.cc b/storage/innobase/buf/buf0lru.cc

index 577f1dae91c..decdf8a27f7 100644

--- a/storage/innobase/buf/buf0lru.cc

+++ b/storage/innobase/buf/buf0lru.cc

@@ -766,6 +766,7 @@ buf_block_t* buf_LRU_get_free_block(bool have_mutex)

 		}

 		memset(&block->page.zip, 0, sizeof block->page.zip);

 		block->skip_flush_check = false;

+		ut_ad(buf_pool.is_uncompressed(block));

 		return(block);

 	}

diff --git a/storage/xtradb/buf/buf0lru.cc b/storage/xtradb/buf/buf0lru.cc

index 13bf5e79f2d..340f9e498c3 100644

--- a/storage/xtradb/buf/buf0lru.cc

+++ b/storage/xtradb/buf/buf0lru.cc

@@ -1124,6 +1124,55 @@ buf_LRU_handle_lack_of_free_blocks(

 	}

 }

+/********************************************************************//**

+Find out if a pointer belongs to a buf_block_t. It can be a pointer to

+the buf_block_t itself or a member of it. This functions checks one of

+the buffer pool instances.

+@return	TRUE if ptr belongs to a buf_block_t struct */

+static

+ibool

+buf_pointer_is_block_field_instance(

+/*================================*/

+	buf_pool_t*	buf_pool,	/*!< in: buffer pool instance */

+	const void*	ptr)		/*!< in: pointer not dereferenced */

+{

+	const buf_chunk_t*		chunk	= buf_pool->chunks;

+	const buf_chunk_t* const	echunk	= chunk + buf_pool->n_chunks;

+

+	/* TODO: protect buf_pool->chunks with a mutex (it will

+	currently remain constant after buf_pool_init()) */

+	while (chunk < echunk) {

+		if (ptr >= (void*) chunk->blocks

+		    && ptr < (void*) (chunk->blocks + chunk->size)) {

+

+			return(TRUE);

+		}

+

+		chunk++;

+	}

+

+	return(FALSE);

+}

+

+/********************************************************************//**

+Find out if a buffer block was created by buf_chunk_init().

+@return	TRUE if "block" has been added to buf_pool->free by buf_chunk_init() */

+static

+ibool

+buf_block_is_uncompressed(

+/*======================*/

+	buf_pool_t*		buf_pool,	/*!< in: buffer pool instance */

+	const buf_block_t*	block)		/*!< in: pointer to block,

+						not dereferenced */

+{

+	if ((((ulint) block) % sizeof *block) != 0) {

+		/* The pointer should be aligned. */

+		return(FALSE);

+	}

+

+	return(buf_pointer_is_block_field_instance(buf_pool, (void*) block));

+}

+

 /** The maximum allowed backoff sleep time duration, microseconds */

 #define MAX_FREE_LIST_BACKOFF_SLEEP 10000

@@ -1187,6 +1236,7 @@ buf_LRU_get_free_block(

 		ut_ad(buf_pool_from_block(block) == buf_pool);

 		memset(&block->page.zip, 0, sizeof block->page.zip);

+		ut_ad(buf_block_is_uncompressed(buf_pool, block));

 		return(block);

 	}

	if (block != NULL) {

		/* If the guess is a compressed page descriptor that

		has been allocated by buf_page_alloc_descriptor(),

		it may have been freed by buf_relocate(). */

		if (!buf_block_is_uncompressed(buf_pool, block)

		    || offset != block->page.offset

		    || space != block->page.space

		    || buf_block_get_state(block) != BUF_BLOCK_FILE_PAGE) {

			/* Our guess was bogus or things have changed

			since. */

			block = guess = NULL;

		} else {

			ut_ad(!block->page.in_zip_hash);

		}

	}

	if (block == NULL) {

		block = (buf_block_t*) buf_page_hash_get_low(

			buf_pool, space, offset, fold);

	}