From 5fa0a690eb4dd80c32b174b395263e2484433862 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?D=C3=A1niel=20B=C3=A1tyai?= Date: Wed, 28 Aug 2019 14:58:35 +0200 Subject: [PATCH] Look up the previous block again after a GC in jmem_heap_realloc_block (#3021) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Garbage collection can create new free blocks in the heap structure as it releases memory, so the previous block needs to be looked up again if a GC happens during a realloc. JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu --- jerry-core/jmem/jmem-heap.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/jerry-core/jmem/jmem-heap.c b/jerry-core/jmem/jmem-heap.c index 05b85463a..7ca7ace67 100644 --- a/jerry-core/jmem/jmem-heap.c +++ b/jerry-core/jmem/jmem-heap.c @@ -516,8 +516,6 @@ jmem_heap_realloc_block (void *ptr, /**< memory region to reallocate */ return block_p; } - jmem_heap_free_t *prev_p = jmem_heap_find_prev (block_p); - if (aligned_new_size < aligned_old_size) { JMEM_VALGRIND_NOACCESS_SPACE (block_p, old_size); @@ -525,7 +523,7 @@ jmem_heap_realloc_block (void *ptr, /**< memory region to reallocate */ JMEM_HEAP_STAT_FREE (old_size); JMEM_HEAP_STAT_ALLOC (new_size); jmem_heap_insert_block ((jmem_heap_free_t *)((uint8_t *) block_p + aligned_new_size), - prev_p, + jmem_heap_find_prev (block_p), aligned_old_size - aligned_new_size); JERRY_CONTEXT (jmem_heap_allocated_size) -= (aligned_old_size - aligned_new_size); @@ -547,6 +545,7 @@ jmem_heap_realloc_block (void *ptr, /**< memory region to reallocate */ ecma_free_unused_memory (JMEM_PRESSURE_LOW); } + jmem_heap_free_t *prev_p = jmem_heap_find_prev (block_p); JMEM_VALGRIND_DEFINED_SPACE (prev_p, sizeof (jmem_heap_free_t)); jmem_heap_free_t * const next_p = JMEM_HEAP_GET_ADDR_FROM_OFFSET (prev_p->next_offset); JMEM_VALGRIND_DEFINED_SPACE (next_p, sizeof (jmem_heap_free_t)); @@ -619,8 +618,15 @@ jmem_heap_realloc_block (void *ptr, /**< memory region to reallocate */ /* jmem_heap_alloc_block_internal will adjust the allocated_size, but insert_block will not, so we reduce it here first, so that the limit calculation remains consistent. */ JERRY_CONTEXT (jmem_heap_allocated_size) -= aligned_old_size; - ret_block_p = jmem_heap_alloc_block_internal (new_size); + + /* jmem_heap_alloc_block_internal may trigger garbage collection, which can create new free blocks + * in the heap structure, so we need to look up the previous block again. */ + if (JERRY_UNLIKELY (JERRY_CONTEXT (ecma_gc_new_objects) == 0)) + { + prev_p = jmem_heap_find_prev (block_p); + } + memcpy (ret_block_p, block_p, old_size); jmem_heap_insert_block (block_p, prev_p, aligned_old_size); }