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-rw-r--r--mm/debug.c46
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 */