From 154bb93c45836e1dafe1e9eb942d3cce084ece19 Mon Sep 17 00:00:00 2001
From: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Thu, 24 Nov 2022 19:36:21 +0800
Subject: [PATCH] mm: Terminate the backtrace array with one NULL pointer

since one entry is enough to identify the end of back trace

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
---
 mm/mempool/mempool.c | 4 ++--
 mm/mm_heap/mm.h      | 6 +++---
 mm/tlsf/mm_tlsf.c    | 4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/mempool/mempool.c b/mm/mempool/mempool.c
index 04bbc0148f..b89a21868f 100644
--- a/mm/mempool/mempool.c
+++ b/mm/mempool/mempool.c
@@ -111,9 +111,9 @@ static inline void mempool_add_backtrace(FAR struct mempool_s *pool,
   if (pool->procfs.backtrace)
     {
       int result = backtrace(buf->backtrace, CONFIG_MM_BACKTRACE);
-      while (result < CONFIG_MM_BACKTRACE)
+      if (result < CONFIG_MM_BACKTRACE)
         {
-          buf->backtrace[result++] = NULL;
+          buf->backtrace[result] = NULL;
         }
     }
   else
diff --git a/mm/mm_heap/mm.h b/mm/mm_heap/mm.h
index 10ee0596ac..952f2ed459 100644
--- a/mm/mm_heap/mm.h
+++ b/mm/mm_heap/mm.h
@@ -89,14 +89,14 @@
          if ((heap)->mm_procfs.backtrace || (tcb && tcb->flags & TCB_FLAG_HEAP_DUMP)) \
            { \
              int n = backtrace(tmp->backtrace, CONFIG_MM_BACKTRACE); \
-             while (n < CONFIG_MM_BACKTRACE) \
+             if (n < CONFIG_MM_BACKTRACE) \
                { \
-                 tmp->backtrace[n++] = NULL; \
+                 tmp->backtrace[n] = NULL; \
                } \
            } \
          else \
            { \
-             tmp->backtrace[0] = 0; \
+             tmp->backtrace[0] = NULL; \
            } \
        } \
      while (0)
diff --git a/mm/tlsf/mm_tlsf.c b/mm/tlsf/mm_tlsf.c
index 46afac384e..291a7ace30 100644
--- a/mm/tlsf/mm_tlsf.c
+++ b/mm/tlsf/mm_tlsf.c
@@ -156,9 +156,9 @@ static void memdump_backtrace(FAR struct mm_heap_s *heap,
       (tcb && tcb->flags & TCB_FLAG_HEAPDUMP))
     {
       int ret = backtrace(dump->backtrace, CONFIG_MM_BACKTRACE);
-      while (ret < CONFIG_MM_BACKTRACE)
+      if (ret < CONFIG_MM_BACKTRACE)
         {
-          dump->backtrace[ret++] = NULL;
+          dump->backtrace[ret] = NULL;
         }
     }
 #  endif