X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=mm%2Fusercopy.c;h=660717a1ea5cd8601488b27ac956a960a9b2f6c9;hb=79e178a57dae819ae724065b47c25720494cc9f2;hp=98e924864554c5dbbd4804f51af20639eb413694;hpb=5825a95fe92566ada2292a65de030850b5cff1da;p=linux.git

diff --git a/mm/usercopy.c b/mm/usercopy.c
index 98e924864554..660717a1ea5c 100644
--- 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. */