Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / kernel / kexec_core.c

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 7045340..5616755 100644 (file)
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -146,6 +146,7 @@ EXPORT_SYMBOL_GPL(kexec_crash_loaded);
  * allocating pages whose destination address we do not care about.
  */
 #define KIMAGE_NO_DEST (-1UL)
+#define PAGE_COUNT(x) (((x) + PAGE_SIZE - 1) >> PAGE_SHIFT)
 
 static struct page *kimage_alloc_page(struct kimage *image,
                                       gfp_t gfp_mask,
@@ -155,6 +156,7 @@ int sanity_check_segment_list(struct kimage *image)
 {
        int i;
        unsigned long nr_segments = image->nr_segments;
+       unsigned long total_pages = 0;
 
        /*
         * Verify we have good destination addresses.  The caller is
@@ -214,6 +216,21 @@ int sanity_check_segment_list(struct kimage *image)
                        return -EINVAL;
        }
 
+       /*
+        * Verify that no more than half of memory will be consumed. If the
+        * request from userspace is too large, a large amount of time will be
+        * wasted allocating pages, which can cause a soft lockup.
+        */
+       for (i = 0; i < nr_segments; i++) {
+               if (PAGE_COUNT(image->segment[i].memsz) > totalram_pages / 2)
+                       return -EINVAL;
+
+               total_pages += PAGE_COUNT(image->segment[i].memsz);
+       }
+
+       if (total_pages > totalram_pages / 2)
+               return -EINVAL;
+
        /*
         * Verify we have good destination addresses.  Normally
         * the caller is responsible for making certain we don't