From ae59d7522a66bca9fb0362477365bd5ac27022ef Mon Sep 17 00:00:00 2001
From: Angus Gratton <angus@espressif.com>
Date: Tue, 31 Jul 2018 14:29:31 +1000
Subject: [PATCH] heap: heap_caps_malloc(..., MALLOC_CAP_32_BIT) should always
 align a 32-bit aligned size

Fixes crash in heap poisoning code if a non-32bit-aligned size is specified.
---
 components/heap/heap_caps.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/components/heap/heap_caps.c b/components/heap/heap_caps.c
index e5a273a0f..90b8821f5 100644
--- a/components/heap/heap_caps.c
+++ b/components/heap/heap_caps.c
@@ -75,9 +75,16 @@ IRAM_ATTR void *heap_caps_malloc( size_t size, uint32_t caps )
         if ((caps & MALLOC_CAP_8BIT) || (caps & MALLOC_CAP_DMA)) {
             return NULL;
         }
-        //If any, EXEC memory should be 32-bit aligned, so round up to the next multiple of 4.
+        caps |= MALLOC_CAP_32BIT; // IRAM is 32-bit accessible RAM
+    }
+
+    if (caps & MALLOC_CAP_32BIT) {
+        /* 32-bit accessible RAM should allocated in 4 byte aligned sizes
+         * (Future versions of ESP-IDF should possibly fail if an invalid size is requested)
+         */
         size = (size + 3) & (~3);
     }
+
     for (int prio = 0; prio < SOC_MEMORY_TYPE_NO_PRIOS; prio++) {
         //Iterate over heaps and check capabilities at this priority
         heap_t *heap;