mm/sparse: more checks on mem_section number
authorGavin Shan <shangw@linux.vnet.ibm.com>
Tue, 31 Jul 2012 23:46:04 +0000 (16:46 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 1 Aug 2012 01:42:49 +0000 (18:42 -0700)
__section_nr() was implemented to retrieve the corresponding memory
section number according to its descriptor.  It's possible that the
specified memory section descriptor doesn't exist in the global array.  So
add more checking on that and report an error for a wrong case.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/sparse.c

index fa933f4..42ca0ea 100644 (file)
@@ -130,6 +130,8 @@ int __section_nr(struct mem_section* ms)
                     break;
        }
 
+       VM_BUG_ON(root_nr == NR_SECTION_ROOTS);
+
        return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
 }