1 files changed, 46 insertions, 0 deletions

diff --git a/mm/debug.c b/mm/debug.c
index bd10aad8539a..cdacba12e09a 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -13,6 +13,7 @@
 #include <trace/events/mmflags.h>
 #include <linux/migrate.h>
 #include <linux/page_owner.h>
+#include <linux/ctype.h>
 
 #include "internal.h"
 
@@ -175,4 +176,49 @@ void dump_mm(const struct mm_struct *mm)
         );
 }
 
+static bool page_init_poisoning __read_mostly = true;
+
+static int __init setup_vm_debug(char *str)
+{
+        bool __page_init_poisoning = true;
+
+        /*
+         * Calling vm_debug with no arguments is equivalent to requesting
+         * to enable all debugging options we can control.
+         */
+        if (*str++ != '=' || !*str)
+                goto out;
+
+        __page_init_poisoning = false;
+        if (*str == '-')
+                goto out;
+
+        while (*str) {
+                switch (tolower(*str)) {
+                case'p':
+                        __page_init_poisoning = true;
+                        break;
+                default:
+                        pr_err("vm_debug option '%c' unknown. skipped\n",
+                               *str);
+                }
+
+                str++;
+        }
+out:
+        if (page_init_poisoning && !__page_init_poisoning)
+                pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
+
+        page_init_poisoning = __page_init_poisoning;
+
+        return 1;
+}
+__setup("vm_debug", setup_vm_debug);
+
+void page_init_poison(struct page *page, size_t size)
+{
+        if (page_init_poisoning)
+                memset(page, PAGE_POISON_PATTERN, size);
+}
+EXPORT_SYMBOL_GPL(page_init_poison);
 #endif          /* CONFIG_DEBUG_VM */