(nuttx) branch master updated: mm/heap: Handle zero memalign alignment

[casaroli]

This is an automated email from the ASF dual-hosted git repository.

casaroli pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new 8773241554a mm/heap: Handle zero memalign alignment
8773241554a is described below

commit 8773241554a3d699eb67c1d54565b9d621d90c2c
Author: chao an <anchao.arc...@bytedance.com>
AuthorDate: Wed Oct 28 14:58:27 2026 +0800

    mm/heap: Handle zero memalign alignment
    
    mm_memalign() accepted a zero alignment because the power-of-two check also
    passes for zero. That could trip the debug alignment assertion with a modulo
    by zero.
    
    Treat zero as a request for the natural malloc alignment so internal callers
    that do not require extra alignment keep the existing allocation semantics.
    
    Signed-off-by: chao an <anchao.arc...@bytedance.com>
---
 mm/mm_heap/mm_memalign.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/mm/mm_heap/mm_memalign.c b/mm/mm_heap/mm_memalign.c
index fecb9b742ed..99fb74f70ea 100644
--- a/mm/mm_heap/mm_memalign.c
+++ b/mm/mm_heap/mm_memalign.c
@@ -62,6 +62,15 @@ FAR void *mm_memalign(FAR struct mm_heap_s *heap, size_t 
alignment,
   size_t allocsize;
   size_t newsize;
 
+  /* Treat zero as a request for the natural malloc alignment.  Some
+   * internal callers pass zero when no extra alignment is required.
+   */
+
+  if (alignment == 0)
+    {
+      alignment = MM_ALIGN;
+    }
+
   /* Make sure that alignment is less than half max size_t */
 
   if (alignment >= (SIZE_MAX / 2))
@@ -94,6 +103,7 @@ FAR void *mm_memalign(FAR struct mm_heap_s *heap, size_t 
alignment,
   if (alignment <= MM_ALIGN)
     {
       FAR void *ptr = mm_malloc(heap, size);
+
       DEBUGASSERT(ptr == NULL || ((uintptr_t)ptr) % alignment == 0);
       return ptr;
     }