Fix get_unmapped_area sanity tests

As noted by Chris Wright, we need to do the full range of tests regardless
of whether MAP_FIXED is set or not, so re-organize get_unmapped_area()
slightly to do the sanity checks unconditionally.

diff --git a/include/linux/err.h b/include/linux/err.h
index 17c55df..ff71d2a 100644 (file)
--- a/include/linux/err.h
+++ b/include/linux/err.h
@@ -13,6 +13,8 @@
  * This should be a per-architecture thing, to allow different
  * error and pointer decisions.
  */
+#define IS_ERR_VALUE(x) unlikely((x) > (unsigned long)-1000L)
+
 static inline void *ERR_PTR(long error)
 {
        return (void *) error;
@@ -25,7 +27,7 @@ static inline long PTR_ERR(const void *ptr)
 
 static inline long IS_ERR(const void *ptr)
 {
-       return unlikely((unsigned long)ptr > (unsigned long)-1000L);
+       return IS_ERR_VALUE((unsigned long)ptr);
 }
 
 #endif /* _LINUX_ERR_H */

diff --git a/mm/mmap.c b/mm/mmap.c
index 63df2d6..de54acd 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1302,37 +1302,40 @@ unsigned long
 get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
                unsigned long pgoff, unsigned long flags)
 {
-       if (flags & MAP_FIXED) {
-               unsigned long ret;
+       unsigned long ret;
 
-               if (addr > TASK_SIZE - len)
-                       return -ENOMEM;
-               if (addr & ~PAGE_MASK)
-                       return -EINVAL;
-               if (file && is_file_hugepages(file))  {
-                       /*
-                        * Check if the given range is hugepage aligned, and
-                        * can be made suitable for hugepages.
-                        */
-                       ret = prepare_hugepage_range(addr, len);
-               } else {
-                       /*
-                        * Ensure that a normal request is not falling in a
-                        * reserved hugepage range.  For some archs like IA-64,
-                        * there is a separate region for hugepages.
-                        */
-                       ret = is_hugepage_only_range(current->mm, addr, len);
-               }
-               if (ret)
-                       return -EINVAL;
-               return addr;
-       }
+       if (!(flags & MAP_FIXED)) {
+               unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 
-       if (file && file->f_op && file->f_op->get_unmapped_area)
-               return file->f_op->get_unmapped_area(file, addr, len,
-                                               pgoff, flags);
+               get_area = current->mm->get_unmapped_area;
+               if (file && file->f_op && file->f_op->get_unmapped_area)
+                       get_area = file->f_op->get_unmapped_area;
+               addr = get_area(file, addr, len, pgoff, flags);
+               if (IS_ERR_VALUE(addr))
+                       return addr;
+       }
 
-       return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
+       if (addr > TASK_SIZE - len)
+               return -ENOMEM;
+       if (addr & ~PAGE_MASK)
+               return -EINVAL;
+       if (file && is_file_hugepages(file))  {
+               /*
+                * Check if the given range is hugepage aligned, and
+                * can be made suitable for hugepages.
+                */
+               ret = prepare_hugepage_range(addr, len);
+       } else {
+               /*
+                * Ensure that a normal request is not falling in a
+                * reserved hugepage range.  For some archs like IA-64,
+                * there is a separate region for hugepages.
+                */
+               ret = is_hugepage_only_range(current->mm, addr, len);
+       }
+       if (ret)
+               return -EINVAL;
+       return addr;
 }
 
 EXPORT_SYMBOL(get_unmapped_area);