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-rw-r--r--include/linux/memory.h6
-rw-r--r--mm/memory.c10
2 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/memory.h b/include/linux/memory.h
index 3fdc10806d31..86a6c0f0518d 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -99,4 +99,10 @@ enum mem_add_context { BOOT, HOTPLUG };
#define hotplug_memory_notifier(fn, pri) do { } while (0)
#endif
+/*
+ * Kernel text modification mutex, used for code patching. Users of this lock
+ * can sleep.
+ */
+extern struct mutex text_mutex;
+
#endif /* _LINUX_MEMORY_H_ */
diff --git a/mm/memory.c b/mm/memory.c
index baa999e87cd2..05fab3bc5b4b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -48,6 +48,8 @@
#include <linux/rmap.h>
#include <linux/module.h>
#include <linux/delayacct.h>
+#include <linux/kprobes.h>
+#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/writeback.h>
#include <linux/memcontrol.h>
@@ -99,6 +101,14 @@ int randomize_va_space __read_mostly =
2;
#endif
+/*
+ * mutex protecting text section modification (dynamic code patching).
+ * some users need to sleep (allocating memory...) while they hold this lock.
+ *
+ * NOT exported to modules - patching kernel text is a really delicate matter.
+ */
+DEFINE_MUTEX(text_mutex);
+
static int __init disable_randmaps(char *s)
{
randomize_va_space = 0;