If the malloc range passed to mem_malloc_init() is at the end of address
range and 'start + size' overflows to 0, following allocations fail as
mem_malloc_end is zero (which looks like uninitialized).

Fix this by subtracting 1 of 'start + size' overflows to zero.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschm...@gmail.com>
---

Changes in v5:
- this patch was 1/2 in v4 but is now 2/2 as the 2nd patch of v4 has
  already been accepted
- rearrange the code to make it only 8 bytes plus in code size for arm
  (which fixes smartweb SPL overflowing)

 common/dlmalloc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/common/dlmalloc.c b/common/dlmalloc.c
index 6f12a18d54..38859ecbd4 100644
--- a/common/dlmalloc.c
+++ b/common/dlmalloc.c
@@ -601,8 +601,12 @@ void *sbrk(ptrdiff_t increment)
 void mem_malloc_init(ulong start, ulong size)
 {
        mem_malloc_start = start;
-       mem_malloc_end = start + size;
        mem_malloc_brk = start;
+       mem_malloc_end = start + size;
+       if (size > mem_malloc_end) {
+               /* overflow: malloc area is at end of address range */
+               mem_malloc_end--;
+       }
 
        debug("using memory %#lx-%#lx for malloc()\n", mem_malloc_start,
              mem_malloc_end);
-- 
2.17.1

_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot

Reply via email to