From patchwork Tue Jan 3 12:49:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 13087444 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 655DEC3DA7D for ; Tue, 3 Jan 2023 12:49:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233308AbjACMth (ORCPT ); Tue, 3 Jan 2023 07:49:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237630AbjACMtc (ORCPT ); Tue, 3 Jan 2023 07:49:32 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 38F3133B; Tue, 3 Jan 2023 04:49:31 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A722F153B; Tue, 3 Jan 2023 04:50:12 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 226433F587; Tue, 3 Jan 2023 04:49:30 -0800 (PST) From: Mark Rutland To: linux-kernel@vger.kernel.org Cc: mark.rutland@arm.com, mhiramat@kernel.org, revest@chromium.org, rostedt@goodmis.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH v2 2/3] ftrace: Export ftrace_free_filter() to modules Date: Tue, 3 Jan 2023 12:49:11 +0000 Message-Id: <20230103124912.2948963-3-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230103124912.2948963-1-mark.rutland@arm.com> References: <20230103124912.2948963-1-mark.rutland@arm.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org Setting filters on an ftrace ops results in some memory being allocated for the filter hashes, which must be freed before the ops can be freed. This can be done by removing every individual element of the hash by calling ftrace_set_filter_ip() or ftrace_set_filter_ips() with `remove` set, but this is somewhat error prone as it's easy to forget to remove an element. Make it easier to clean this up by exporting ftrace_free_filter(), which can be used to clean up all of the filter hashes after an ftrace_ops has been unregistered. Using this, fix the ftrace-direct* samples to free hashes prior to being unloaded. All other code either removes individual filters explicitly or is built-in and already calls ftrace_free_filter(). Signed-off-by: Mark Rutland Reviewed-by: Steven Rostedt (Google) Cc: Florent Revest Cc: Masami Hiramatsu Reviewed-by: Masami Hiramatsu (Google) --- kernel/trace/ftrace.c | 23 ++++++++++++++++++++- samples/ftrace/ftrace-direct-multi-modify.c | 1 + samples/ftrace/ftrace-direct-multi.c | 1 + 3 files changed, 24 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 442438b93fe98..750aa3f08b25a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1248,12 +1248,17 @@ static void free_ftrace_hash_rcu(struct ftrace_hash *hash) call_rcu(&hash->rcu, __free_ftrace_hash_rcu); } +/** + * ftrace_free_filter - remove all filters for an ftrace_ops + * @ops - the ops to remove the filters from + */ void ftrace_free_filter(struct ftrace_ops *ops) { ftrace_ops_init(ops); free_ftrace_hash(ops->func_hash->filter_hash); free_ftrace_hash(ops->func_hash->notrace_hash); } +EXPORT_SYMBOL_GPL(ftrace_free_filter); static struct ftrace_hash *alloc_ftrace_hash(int size_bits) { @@ -5839,6 +5844,10 @@ EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi); * * Filters denote which functions should be enabled when tracing is enabled * If @ip is NULL, it fails to update filter. + * + * This can allocate memory which must be freed before @ops can be freed, + * either by removing each filtered addr or by using + * ftrace_free_filter(@ops). */ int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip, int remove, int reset) @@ -5858,7 +5867,11 @@ EXPORT_SYMBOL_GPL(ftrace_set_filter_ip); * * Filters denote which functions should be enabled when tracing is enabled * If @ips array or any ip specified within is NULL , it fails to update filter. - */ + * + * This can allocate memory which must be freed before @ops can be freed, + * either by removing each filtered addr or by using + * ftrace_free_filter(@ops). +*/ int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt, int remove, int reset) { @@ -5900,6 +5913,10 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len, * * Filters denote which functions should be enabled when tracing is enabled. * If @buf is NULL and reset is set, all functions will be enabled for tracing. + * + * This can allocate memory which must be freed before @ops can be freed, + * either by removing each filtered addr or by using + * ftrace_free_filter(@ops). */ int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf, int len, int reset) @@ -5919,6 +5936,10 @@ EXPORT_SYMBOL_GPL(ftrace_set_filter); * Notrace Filters denote which functions should not be enabled when tracing * is enabled. If @buf is NULL and reset is set, all functions will be enabled * for tracing. + * + * This can allocate memory which must be freed before @ops can be freed, + * either by removing each filtered addr or by using + * ftrace_free_filter(@ops). */ int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf, int len, int reset) diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c index d52370cad0b6e..a825dbd2c9cfd 100644 --- a/samples/ftrace/ftrace-direct-multi-modify.c +++ b/samples/ftrace/ftrace-direct-multi-modify.c @@ -152,6 +152,7 @@ static void __exit ftrace_direct_multi_exit(void) { kthread_stop(simple_tsk); unregister_ftrace_direct_multi(&direct, my_tramp); + ftrace_free_filter(&direct); } module_init(ftrace_direct_multi_init); diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c index ec1088922517d..d955a26506053 100644 --- a/samples/ftrace/ftrace-direct-multi.c +++ b/samples/ftrace/ftrace-direct-multi.c @@ -79,6 +79,7 @@ static int __init ftrace_direct_multi_init(void) static void __exit ftrace_direct_multi_exit(void) { unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp); + ftrace_free_filter(&direct); } module_init(ftrace_direct_multi_init);