Commit 81bcfe5e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-v4.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull tracing fixes from Steven Rostedt:
 "Alexei discovered a race condition in modules failing to load that can
  cause a ftrace check to trigger and disable ftrace.

  This is because of the way modules are registered to ftrace. Their
  functions are loaded in the ftrace function tables but set to
  "disabled" since they are still in the process of being loaded by the
  module. After the module is finished, it calls back into the ftrace
  infrastructure to enable it.

  Looking deeper into the locations that access all the functions in the
  table, I found more locations that should ignore the disabled ones"

* tag 'trace-v4.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Add more checks for FTRACE_FL_DISABLED in processing ip records
  ftrace: Ignore FTRACE_FL_DISABLED while walking dyn_ftrace records
parents 80fc2f7f 546fece4

kernel/trace/ftrace.c

+23 −1
Original line number Original line Diff line number Diff line
@@ -1862,6 +1862,10 @@ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, 




	/* Update rec->flags */

	/* Update rec->flags */

	do_for_each_ftrace_rec(pg, rec) {

	do_for_each_ftrace_rec(pg, rec) {



		if (rec->flags & FTRACE_FL_DISABLED)

			continue;



		/* We need to update only differences of filter_hash */

		/* We need to update only differences of filter_hash */

		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);

		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);

		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);

		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
@@ -1884,6 +1888,10 @@ rollback: 




	/* Roll back what we did above */

	/* Roll back what we did above */

	do_for_each_ftrace_rec(pg, rec) {

	do_for_each_ftrace_rec(pg, rec) {



		if (rec->flags & FTRACE_FL_DISABLED)

			continue;



		if (rec == end)

		if (rec == end)

			goto err_out;

			goto err_out;
@@ -2397,6 +2405,10 @@ void __weak ftrace_replace_code(int enable) 
		return;

		return;





	do_for_each_ftrace_rec(pg, rec) {

	do_for_each_ftrace_rec(pg, rec) {



		if (rec->flags & FTRACE_FL_DISABLED)

			continue;



		failed = __ftrace_replace_code(rec, enable);

		failed = __ftrace_replace_code(rec, enable);

		if (failed) {

		if (failed) {

			ftrace_bug(failed, rec);

			ftrace_bug(failed, rec);
@@ -2763,7 +2775,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) 
		struct dyn_ftrace *rec;

		struct dyn_ftrace *rec;





		do_for_each_ftrace_rec(pg, rec) {

		do_for_each_ftrace_rec(pg, rec) {

			if (FTRACE_WARN_ON_ONCE(rec->flags))

			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))

				pr_warn("  %pS flags:%lx\n",

				pr_warn("  %pS flags:%lx\n",

					(void *)rec->ip, rec->flags);

					(void *)rec->ip, rec->flags);

		} while_for_each_ftrace_rec();

		} while_for_each_ftrace_rec();
@@ -3598,6 +3610,10 @@ match_records(struct ftrace_hash *hash, char *func, int len, char *mod) 
		goto out_unlock;

		goto out_unlock;





	do_for_each_ftrace_rec(pg, rec) {

	do_for_each_ftrace_rec(pg, rec) {



		if (rec->flags & FTRACE_FL_DISABLED)

			continue;



		if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {

		if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {

			ret = enter_record(hash, rec, clear_filter);

			ret = enter_record(hash, rec, clear_filter);

			if (ret < 0) {

			if (ret < 0) {
@@ -3793,6 +3809,9 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, 




	do_for_each_ftrace_rec(pg, rec) {

	do_for_each_ftrace_rec(pg, rec) {





		if (rec->flags & FTRACE_FL_DISABLED)

			continue;



		if (!ftrace_match_record(rec, &func_g, NULL, 0))

		if (!ftrace_match_record(rec, &func_g, NULL, 0))

			continue;

			continue;
@@ -4685,6 +4704,9 @@ ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer) 




	do_for_each_ftrace_rec(pg, rec) {

	do_for_each_ftrace_rec(pg, rec) {





		if (rec->flags & FTRACE_FL_DISABLED)

			continue;



		if (ftrace_match_record(rec, &func_g, NULL, 0)) {

		if (ftrace_match_record(rec, &func_g, NULL, 0)) {

			/* if it is in the array */

			/* if it is in the array */

			exists = false;

			exists = false;

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