Merge branch 'slab/urgent' into for-linus

[karo-tx-linux.git] / kernel / trace / trace_functions_graph.c

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 8b592418d8b28953a28e40c2202a50cb2b40dd37..d2249abafb53ed66430678f99d7d7642962e7d90 100644 (file)
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -57,7 +57,8 @@ static struct tracer_flags tracer_flags = {
 
 /* Add a function return address to the trace stack on thread info.*/
 int
-ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
+ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
+                        unsigned long frame_pointer)
 {
        unsigned long long calltime;
        int index;
@@ -85,6 +86,7 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
        current->ret_stack[index].func = func;
        current->ret_stack[index].calltime = calltime;
        current->ret_stack[index].subtime = 0;
+       current->ret_stack[index].fp = frame_pointer;
        *depth = index;
 
        return 0;
@@ -92,7 +94,8 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
 
 /* Retrieve a function return address to the trace stack on thread info.*/
 static void
-ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
+                       unsigned long frame_pointer)
 {
        int index;
 
@@ -106,6 +109,31 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
                return;
        }
 
+#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
+       /*
+        * The arch may choose to record the frame pointer used
+        * and check it here to make sure that it is what we expect it
+        * to be. If gcc does not set the place holder of the return
+        * address in the frame pointer, and does a copy instead, then
+        * the function graph trace will fail. This test detects this
+        * case.
+        *
+        * Currently, x86_32 with optimize for size (-Os) makes the latest
+        * gcc do the above.
+        */
+       if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+               ftrace_graph_stop();
+               WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
+                    "  from func %pF return to %lx\n",
+                    current->ret_stack[index].fp,
+                    frame_pointer,
+                    (void *)current->ret_stack[index].func,
+                    current->ret_stack[index].ret);
+               *ret = (unsigned long)panic;
+               return;
+       }
+#endif
+
        *ret = current->ret_stack[index].ret;
        trace->func = current->ret_stack[index].func;
        trace->calltime = current->ret_stack[index].calltime;
@@ -117,12 +145,12 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
  * Send the trace to the ring-buffer.
  * @return the original return address.
  */
-unsigned long ftrace_return_to_handler(void)
+unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 {
        struct ftrace_graph_ret trace;
        unsigned long ret;
 
-       ftrace_pop_return_trace(&trace, &ret);
+       ftrace_pop_return_trace(&trace, &ret, frame_pointer);
        trace.rettime = trace_clock_local();
        ftrace_graph_return(&trace);
        barrier();