[PATCH] mm/memblock.c: Correctly check whether to trim a block

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Currently in __memblock_remove, the check to trim the top of
a block off only checks if the requested base is less than the
memblock end. If the end of the requested region is equal to
the start of a memblock, this will incorrectly try to remove
the block, possibly causing an integer underflow:

   ---------------------------------------
   |                    |                |
   |                    |                |
  base              end = rgn->base    rend

An additional check is needed to see if the end of the requested
region is greater than the memblock region:

   ----------------------
   |                     |
   |                     |
  rgn->base    base     rend      end
                |                  |
                |                  |
                --------------------

Signed-off-by: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
---
 mm/memblock.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index 5338237..e174ee0 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -459,7 +459,7 @@ static long __init_memblock __memblock_remove(struct memblock_type *type,
 		}
 
 		/* And check if we need to trim the top of a block */
-		if (base < rend)
+		if (base < rend && end > rend)
 			rgn->size -= rend - base;
 
 	}
-- 
1.7.8.3

--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [Linux for Sparc]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux