2 files changed, 17 insertions, 2 deletions

diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 83c1bc8d2e8a..456a304b8172 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -299,6 +299,8 @@ do {									\
 
 #ifdef CONFIG_X86_32
 
+#define STACK_RND_MASK (0x7ff)
+
 #define VDSO_HIGH_BASE          (__fix_to_virt(FIX_VDSO))
 
 #define ARCH_DLINFO             ARCH_DLINFO_IA32(vdso_enabled)
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index 165829600566..c8191defc38a 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -29,13 +29,26 @@
 #include <linux/random.h>
 #include <linux/limits.h>
 #include <linux/sched.h>
+#include <asm/elf.h>
+
+static unsigned int stack_maxrandom_size(void)
+{
+        unsigned int max = 0;
+        if ((current->flags & PF_RANDOMIZE) &&
+                !(current->personality & ADDR_NO_RANDOMIZE)) {
+                max = ((-1U) & STACK_RND_MASK) << PAGE_SHIFT;
+        }
+
+        return max;
+}
+
 
 /*
  * Top of mmap area (just below the process stack).
  *
- * Leave an at least ~128 MB hole.
+ * Leave an at least ~128 MB hole with possible stack randomization.
  */
-#define MIN_GAP (128*1024*1024)
+#define MIN_GAP (128*1024*1024UL + stack_maxrandom_size())
 #define MAX_GAP (TASK_SIZE/6*5)
 
 /*