Re: [uclibc-ng-devel] [PATCH] malloc: Add missing locks for some paths (valloc/memalign/posix_memalign)

The internal heap structures were not protected properly in memalign(). If multiple threads were concurrently allocating memory and one of them were requesting aligned memory via valloc,memalign or posix_memalign the internal heap data structures could be corrupted. Signed-off-by: Kjetil Oftedal &lt;oftedal(a)gmail.com&gt; --- libc/stdlib/malloc/memalign.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/libc/stdlib/malloc/memalign.c b/libc/stdlib/malloc/memalign.c index 74d5dbd..0d3de67 100644 --- a/libc/stdlib/malloc/memalign.c +++ b/libc/stdlib/malloc/memalign.c @@ -77,7 +77,9 @@ memalign (size_t alignment, size_t size) init_size = addr - tot_addr; } + __heap_lock (&__malloc_heap_lock); __heap_free (heap, base, init_size); + __heap_unlock (&__malloc_heap_lock); /* Remember that we've freed the initial part of MEM. */ base += init_size; @@ -85,9 +87,11 @@ memalign (size_t alignment, size_t size) /* Return the end part of MEM to the heap, unless it's too small. */ end_addr = addr + size; - if (end_addr + MALLOC_REALLOC_MIN_FREE_SIZE < tot_end_addr) + if (end_addr + MALLOC_REALLOC_MIN_FREE_SIZE < tot_end_addr) { + __heap_lock (&__malloc_heap_lock); __heap_free (heap, (void *)end_addr, tot_end_addr - end_addr); - else + __heap_unlock (&__malloc_heap_lock); + } else /* We didn't free the end, so include it in the size. */ end_addr = tot_end_addr;