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Commit a4500b84 authored by Abhishek Sagar's avatar Abhishek Sagar Committed by Ingo Molnar
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ftrace: fix "notrace" filtering priority 



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: default avatarAbhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 20764ff1

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);