test/mem: disable ASan when accessing unallocated memory

[dpdk.git] / lib / eal / common / malloc_heap.c

diff --git a/lib/eal/common/malloc_heap.c b/lib/eal/common/malloc_heap.c
index 6c572b6..a3d26fc 100644 (file)
--- a/lib/eal/common/malloc_heap.c
+++ b/lib/eal/common/malloc_heap.c
@@ -861,6 +861,7 @@ malloc_heap_free(struct malloc_elem *elem)
        struct rte_memseg_list *msl;
        unsigned int i, n_segs, before_space, after_space;
        int ret;
+       bool unmapped = false;
        const struct internal_config *internal_conf =
                eal_get_internal_configuration();
 
@@ -1027,6 +1028,9 @@ malloc_heap_free(struct malloc_elem *elem)
                request_to_primary(&req);
        }
 
+       /* we didn't exit early, meaning we have unmapped some pages */
+       unmapped = true;
+
        RTE_LOG(DEBUG, EAL, "Heap on socket %d was shrunk by %zdMB\n",
                msl->socket_id, aligned_len >> 20ULL);
 
@@ -1034,6 +1038,37 @@ malloc_heap_free(struct malloc_elem *elem)
 free_unlock:
        asan_set_freezone(asan_ptr, asan_data_len);
 
+       /* if we unmapped some memory, we need to do additional work for ASan */
+       if (unmapped) {
+               void *asan_end = RTE_PTR_ADD(asan_ptr, asan_data_len);
+               void *aligned_end = RTE_PTR_ADD(aligned_start, aligned_len);
+               void *aligned_trailer = RTE_PTR_SUB(aligned_start,
+                               MALLOC_ELEM_TRAILER_LEN);
+
+               /*
+                * There was a memory area that was unmapped. This memory area
+                * will have to be marked as available for ASan, because we will
+                * want to use it next time it gets mapped again. The OS memory
+                * protection should trigger a fault on access to these areas
+                * anyway, so we are not giving up any protection.
+                */
+               asan_set_zone(aligned_start, aligned_len, 0x00);
+
+               /*
+                * ...however, when we unmap pages, we create new free elements
+                * which might have been marked as "freed" with an earlier
+                * `asan_set_freezone` call. So, if there is an area past the
+                * unmapped space that was marked as freezone for ASan, we need
+                * to mark the malloc header as available.
+                */
+               if (asan_end > aligned_end)
+                       asan_set_zone(aligned_end, MALLOC_ELEM_HEADER_LEN, 0x00);
+
+               /* if there's space before unmapped memory, mark as available */
+               if (asan_ptr < aligned_start)
+                       asan_set_zone(aligned_trailer, MALLOC_ELEM_TRAILER_LEN, 0x00);
+       }
+
        rte_spinlock_unlock(&(heap->lock));
        return ret;
 }