memblock: Add debug markers at the end of the array

Since we allocate one more than needed, why not do a bit of sanity checking
here to ensure we don't walk past the end of the array ?

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index 3c474502d92b..a925866e1455 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/bitops.h>
+#include <linux/poison.h>
 #include <linux/memblock.h>
 
 struct memblock memblock;
@@ -112,6 +113,10 @@ void __init memblock_init(void)
         memblock.reserved.regions       = memblock_reserved_init_regions;
         memblock.reserved.max   = INIT_MEMBLOCK_REGIONS;
 
+        /* Write a marker in the unused last array entry */
+        memblock.memory.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
+        memblock.reserved.regions[INIT_MEMBLOCK_REGIONS].base = (phys_addr_t)RED_INACTIVE;
+
         /* Create a dummy zero size MEMBLOCK which will get coalesced away later.
          * This simplifies the memblock_add() code below...
          */
@@ -131,6 +136,12 @@ void __init memblock_analyze(void)
 {
         int i;
 
+        /* Check marker in the unused last array entry */
+        WARN_ON(memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS].base
+                != (phys_addr_t)RED_INACTIVE);
+        WARN_ON(memblock_reserved_init_regions[INIT_MEMBLOCK_REGIONS].base
+                != (phys_addr_t)RED_INACTIVE);
+
         memblock.memory_size = 0;
 
         for (i = 0; i < memblock.memory.cnt; i++)