From f7aad4e1a8221210db7eb434349cc6fe87aeee8c Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 10 Sep 2014 10:42:46 -0400 Subject: [PATCH] ftrace: Set callback to ftrace_stub when no ops are registered The clean up that adds the helper function ftrace_ops_get_func() caused the default function to not change when DYNAMIC_FTRACE was not set and no ftrace_ops were registered. Although static tracing is not very useful (not having DYNAMIC_FTRACE set), it is still supported and we don't want to break it. Clean up the if statement even more to specifically have the default function call ftrace_stub when no ftrace_ops are registered. This fixes the small bug for static tracing as well as makes the code a bit more understandable. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index dabf734f909c..708aea493d96 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -253,18 +253,25 @@ static void update_ftrace_function(void) { ftrace_func_t func; + /* + * Prepare the ftrace_ops that the arch callback will use. + * If there's only one ftrace_ops registered, the ftrace_ops_list + * will point to the ops we want. + */ + set_function_trace_op = ftrace_ops_list; + + /* If there's no ftrace_ops registered, just call the stub function */ + if (ftrace_ops_list == &ftrace_list_end) { + func = ftrace_stub; + /* * If we are at the end of the list and this ops is * recursion safe and not dynamic and the arch supports passing ops, * then have the mcount trampoline call the function directly. */ - if (ftrace_ops_list == &ftrace_list_end || - (ftrace_ops_list->next == &ftrace_list_end)) { - - /* Set the ftrace_ops that the arch callback uses */ - set_function_trace_op = ftrace_ops_list; - + } else if (ftrace_ops_list->next == &ftrace_list_end) { func = ftrace_ops_get_func(ftrace_ops_list); + } else { /* Just use the default ftrace_ops */ set_function_trace_op = &ftrace_list_end; -- 2.20.1