1 files changed, 39 insertions, 9 deletions

diff --git a/kernel/extable.c b/kernel/extable.c
index e136ed8d82ba..7f8f263f8524 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -15,11 +15,22 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
+#include <linux/ftrace.h>
+#include <linux/memory.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/init.h>
-#include <linux/ftrace.h>
-#include <asm/uaccess.h>
+
 #include <asm/sections.h>
+#include <asm/uaccess.h>
+
+/*
+ * 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);
 
 extern struct exception_table_entry __start___ex_table[];
 extern struct exception_table_entry __stop___ex_table[];
@@ -41,31 +52,50 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
         return e;
 }
 
-__notrace_funcgraph int core_kernel_text(unsigned long addr)
+static inline int init_kernel_text(unsigned long addr)
+{
+        if (addr >= (unsigned long)_sinittext &&
+            addr <= (unsigned long)_einittext)
+                return 1;
+        return 0;
+}
+
+int core_kernel_text(unsigned long addr)
 {
         if (addr >= (unsigned long)_stext &&
             addr <= (unsigned long)_etext)
                 return 1;
 
         if (system_state == SYSTEM_BOOTING &&
-            addr >= (unsigned long)_sinittext &&
-            addr <= (unsigned long)_einittext)
+            init_kernel_text(addr))
                 return 1;
         return 0;
 }
 
-__notrace_funcgraph int __kernel_text_address(unsigned long addr)
+int __kernel_text_address(unsigned long addr)
 {
         if (core_kernel_text(addr))
                 return 1;
-        return __module_text_address(addr) != NULL;
+        if (is_module_text_address(addr))
+                return 1;
+        /*
+         * There might be init symbols in saved stacktraces.
+         * Give those symbols a chance to be printed in
+         * backtraces (such as lockdep traces).
+         *
+         * Since we are after the module-symbols check, there's
+         * no danger of address overlap:
+         */
+        if (init_kernel_text(addr))
+                return 1;
+        return 0;
 }
 
 int kernel_text_address(unsigned long addr)
 {
         if (core_kernel_text(addr))
                 return 1;
-        return module_text_address(addr) != NULL;
+        return is_module_text_address(addr);
 }
 
 /*
@@ -81,5 +111,5 @@ int func_ptr_is_kernel_text(void *ptr)
         addr = (unsigned long) dereference_function_descriptor(ptr);
         if (core_kernel_text(addr))
                 return 1;
-        return module_text_address(addr) != NULL;
+        return is_module_text_address(addr);
 }