Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[linux-2.6-block.git] / mm / usercopy.c

diff --git a/mm/usercopy.c b/mm/usercopy.c
index 98e924864554c5dbbd4804f51af20639eb413694..660717a1ea5cd8601488b27ac956a960a9b2f6c9 100644 (file)
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -11,6 +11,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/mm.h>
+#include <linux/highmem.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/sched/task.h>
@@ -227,7 +228,12 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
        if (!virt_addr_valid(ptr))
                return;
 
-       page = virt_to_head_page(ptr);
+       /*
+        * When CONFIG_HIGHMEM=y, kmap_to_page() will give either the
+        * highmem page or fallback to virt_to_page(). The following
+        * is effectively a highmem-aware virt_to_head_page().
+        */
+       page = compound_head(kmap_to_page((void *)ptr));
 
        if (PageSlab(page)) {
                /* Check slab allocator for flags and size. */