malloc: check for heap corruption

Previous code checked for both first/last elements being NULL,
but if they weren't, the expectation was that they're both
non-NULL, which will be the case under normal conditions, but
may not be the case due to heap structure corruption.

Coverity issue: 272566
Fixes: bb372060dad4 ("malloc: make heap a doubly-linked list")

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>

diff --git a/lib/librte_eal/common/malloc_elem.c b/lib/librte_eal/common/malloc_elem.c
index ee79dcd..af81961 100644 (file)
--- a/lib/librte_eal/common/malloc_elem.c
+++ b/lib/librte_eal/common/malloc_elem.c
@@ -49,6 +49,12 @@ malloc_elem_insert(struct malloc_elem *elem)
        struct malloc_elem *prev_elem, *next_elem;
        struct malloc_heap *heap = elem->heap;
 
+       /* first and last elements must be both NULL or both non-NULL */
+       if ((heap->first == NULL) != (heap->last == NULL)) {
+               RTE_LOG(ERR, EAL, "Heap is probably corrupt\n");
+               return;
+       }
+
        if (heap->first == NULL && heap->last == NULL) {
                /* if empty heap */
                heap->first = elem;