hugetlbfs: check for pgoff value overflow

[pandora-kernel.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 390f0ac..a489d93 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -18,6 +18,7 @@
 #include <linux/bootmem.h>
 #include <linux/sysfs.h>
 #include <linux/slab.h>
+#include <linux/mmdebug.h>
 #include <linux/rmap.h>
 #include <linux/swap.h>
 #include <linux/swapops.h>
@@ -3097,6 +3098,14 @@ int hugetlb_reserve_pages(struct inode *inode,
        struct hstate *h = hstate_inode(inode);
        struct hugepage_subpool *spool = subpool_inode(inode);
 
+       /* This should never happen */
+       if (from > to) {
+#ifdef CONFIG_DEBUG_VM
+               WARN(1, "%s called with a negative range\n", __func__);
+#endif
+               return -EINVAL;
+       }
+
        /*
         * Only apply hugepage reservation if asked. At fault time, an
         * attempt will be made for VM_NORESERVE to allocate a page