tracing: Fix infinite recursion in ftrace_update_pid_func()
authorMatt Fleming <matthew.fleming@imgtec.com>
Mon, 28 Sep 2009 15:43:01 +0000 (16:43 +0100)
committerIngo Molnar <mingo@elte.hu>
Thu, 1 Oct 2009 06:19:24 +0000 (08:19 +0200)
When CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST is enabled
__ftrace_trace_function contains the current trace function, not
ftrace_trace_function.

In ftrace_update_pid_func() we currently incorrectly assign the
value of ftrace_trace_function to __ftrace_trace_funcion before
returning.

Without this patch it is possible to execute an infinite recursion
whereby ftrace_test_stop_func() calls __ftrace_trace_function,
which was assigned ftrace_test_stop_func() in
ftrace_update_pid_func().

Signed-off-by: Matt Fleming <matthew.fleming@imgtec.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1254152581-18347-1-git-send-email-matt@console-pimps.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/trace/ftrace.c

index 46592feab5a6b0cf47e5cc147f43e1669efcf712..3724756e41ca9771d311101a38d2f408d416ef6a 100644 (file)
@@ -225,7 +225,11 @@ static void ftrace_update_pid_func(void)
        if (ftrace_trace_function == ftrace_stub)
                return;
 
+#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
        func = ftrace_trace_function;
+#else
+       func = __ftrace_trace_function;
+#endif
 
        if (ftrace_pid_trace) {
                set_ftrace_pid_function(func);