* 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,
{
int i;
unsigned long nr_segments = image->nr_segments;
+ unsigned long total_pages = 0;
/*
* Verify we have good destination addresses. The caller is
}
/*
+ * 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
* attempt to load the new image into invalid or reserved