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Commit 6912896e authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
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ftrace: add ftrace warn on to disable ftrace 



Add ftrace warn on to disable ftrace as well as report a warning.

[ Thanks to Andrew Morton for suggesting using the WARN_ON return value ]

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 81adbdc0

kernel/trace/ftrace.c

+19 −10
Original line number Diff line number Diff line
@@ -32,6 +32,18 @@ 


#include "trace.h"



#define FTRACE_WARN_ON(cond)			\

	do {					\

		if (WARN_ON(cond))		\

			ftrace_kill();		\

	} while (0)



#define FTRACE_WARN_ON_ONCE(cond)		\

	do {					\

		if (WARN_ON_ONCE(cond))		\

			ftrace_kill();		\

	} while (0)



/* ftrace_enabled is a method to turn ftrace on or off */

int ftrace_enabled __read_mostly;

static int last_ftrace_enabled;
@@ -363,10 +375,8 @@ static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip) 
		rec = ftrace_free_records;



		if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {

			WARN_ON_ONCE(1);

			FTRACE_WARN_ON_ONCE(1);

			ftrace_free_records = NULL;

			ftrace_disabled = 1;

			ftrace_enabled = 0;

			return NULL;

		}
@@ -415,7 +425,7 @@ ftrace_record_ip(unsigned long ip) 


	key = hash_long(ip, FTRACE_HASHBITS);



	WARN_ON_ONCE(key >= FTRACE_HASHSIZE);

	FTRACE_WARN_ON_ONCE(key >= FTRACE_HASHSIZE);



	if (ftrace_ip_in_hash(ip, key))

		goto out;
@@ -607,12 +617,12 @@ ftrace_code_disable(struct dyn_ftrace *rec) 
	if (ret) {

		switch (ret) {

		case -EFAULT:

			WARN_ON_ONCE(1);

			FTRACE_WARN_ON_ONCE(1);

			pr_info("ftrace faulted on modifying ");

			print_ip_sym(ip);

			break;

		case -EINVAL:

			WARN_ON_ONCE(1);

			FTRACE_WARN_ON_ONCE(1);

			pr_info("ftrace failed to modify ");

			print_ip_sym(ip);

			print_ip_ins(" expected: ", call);
@@ -621,12 +631,12 @@ ftrace_code_disable(struct dyn_ftrace *rec) 
			printk(KERN_CONT "\n");

			break;

		case -EPERM:

			WARN_ON_ONCE(1);

			FTRACE_WARN_ON_ONCE(1);

			pr_info("ftrace faulted on writing ");

			print_ip_sym(ip);

			break;

		default:

			WARN_ON_ONCE(1);

			FTRACE_WARN_ON_ONCE(1);

			pr_info("ftrace faulted on unknown error ");

			print_ip_sym(ip);

		}
@@ -1722,8 +1732,7 @@ static int ftraced(void *ignore) 
					ftrace_update_cnt != 1 ? "s" : "",

					ftrace_update_tot_cnt,

					usecs, usecs != 1 ? "s" : "");

				ftrace_disabled = 1;

				WARN_ON_ONCE(1);

				FTRACE_WARN_ON_ONCE(1);

			}

		}

		mutex_unlock(&ftraced_lock);