1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 0927bb158ffc..76228525acd0 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/module.h>
+#include <linux/memory.h>
 
 #include <trace/syscall.h>
 
@@ -34,16 +35,25 @@
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 int ftrace_arch_code_modify_prepare(void)
+    __acquires(&text_mutex)
 {
+	/*
+	 * Need to grab text_mutex to prevent a race from module loading
+	 * and live kernel patching from changing the text permissions while
+	 * ftrace has it set to "read/write".
+	 */
+	mutex_lock(&text_mutex);
 	set_kernel_text_rw();
 	set_all_modules_text_rw();
 	return 0;
 }
 
 int ftrace_arch_code_modify_post_process(void)
+    __releases(&text_mutex)
 {
 	set_all_modules_text_ro();
 	set_kernel_text_ro();
+	mutex_unlock(&text_mutex);
 	return 0;
 }