ftrace: fix "notrace" filtering priority (a4500b84) · Commits · 戴 / test

This is a fix to give notrace filter rules priority over "set_ftrace_filter" rules. This fix ensures that functions which are set to be filtered and are concurrently marked as "notrace" don't get recorded. As of now, if a record is marked as FTRACE_FL_FILTER and is enabled, then the notrace flag is not checked. Tested on x86-32. Signed-off-by:

Abhishek Sagar <sagar.abhishek@gmail.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

kernel/trace/ftrace.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -355,20 +355,26 @@ __ftrace_replace_code(struct dyn_ftrace *rec,
		* If this record is set not to trace then
		* do nothing.
		*
		* If this record is set not to trace and
		* it is enabled then disable it.
		*
		* If this record is not set to be filtered and
		* it is enabled, disable it.
		*/
		fl = rec->flags & (FTRACE_FL_FILTER \| FTRACE_FL_ENABLED);

		fl = rec->flags & (FTRACE_FL_FILTER \| FTRACE_FL_NOTRACE \|
		FTRACE_FL_ENABLED);

		if ((fl == (FTRACE_FL_FILTER \| FTRACE_FL_ENABLED)) \|\|
		(fl == 0) \|\| (rec->flags & FTRACE_FL_NOTRACE))
		(fl == (FTRACE_FL_FILTER \| FTRACE_FL_NOTRACE)) \|\|
		!fl \|\| (fl == FTRACE_FL_NOTRACE))
		return 0;

		/*
		* If it is enabled disable it,
		* otherwise enable it!
		*/
		if (fl == FTRACE_FL_ENABLED) {
		if (fl & FTRACE_FL_ENABLED) {
		/* swap new and old */
		new = old;
		old = ftrace_call_replace(ip, FTRACE_ADDR);

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