From mboxrd@z Thu Jan 1 00:00:00 1970 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 615CFC38145 for ; Wed, 7 Sep 2022 08:51:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229719AbiIGIvx (ORCPT ); Wed, 7 Sep 2022 04:51:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229514AbiIGIvp (ORCPT ); Wed, 7 Sep 2022 04:51:45 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04BD99080E; Wed, 7 Sep 2022 01:51:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5F513B81ADB; Wed, 7 Sep 2022 08:51:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 834E1C433D7; Wed, 7 Sep 2022 08:51:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662540701; bh=t96HpRLLdQhSB9aqtR6pVBEsmGcqgnccAYCDAYDxrZI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pej6dZXuqndW9LHaGY7P+hS8DWzEosmvIK/d9MTAq8NJyzVr7kvn1T2a7Z9uIWJHm JdB5zB2roMS8huTQrr0OTW3vkjFBt4kcE7EjeEiDpmBwEhyjz8xiu7acE4FOV9o2oP LlVq820maB3skzJgcJhNEdgVEB1N1RuC38SF9HjrNJi/XAO+gOF35a2SYbxHIojjcM 9X/RVXqYoQH278BAiBJOPTd0i/aj3yTv16Y+FyL8i7SCdLEOnMXAWdWI9mQ/wAFZig ZMGCTb1FZkHS9y77ErbOYdPVa7/WVpPrp3TlD+AFODoBG2yPEiP5Nq8J0wb+3gDgCG 9GZb1ATE9/G3g== Date: Wed, 7 Sep 2022 17:51:36 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: Jianlin Lv , corbet@lwn.net, mingo@redhat.com, jianlv@ebay.com, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Masami Hiramatsu , Tom Zanussi , bpf@vger.kernel.org Subject: Re: [PATCH v2] tracing/kprobes: Add method to display private kprobes in tracefs Message-Id: <20220907175136.96b05b241e650de21eb661e6@kernel.org> In-Reply-To: <20220906111214.0dd113cd@gandalf.local.home> References: <20220725062334.1778-1-iecedge@gmail.com> <20220906111214.0dd113cd@gandalf.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Adding bpf ML] On Tue, 6 Sep 2022 11:12:14 -0400 Steven Rostedt wrote: > > [ Adding Masami and Tom ] > > On Mon, 25 Jul 2022 06:23:34 +0000 > Jianlin Lv wrote: > > > The private kprobes are not added to the global list dyn_event_list, > > so there is a missing interface to show probe hit and probe miss. > > This patch adds a profiling interface to check the number of hits or > > misses for private kprobes. > > Masami, what do you think of this patch? I discussed it with BPF people when it was introduced and they didn't want to show up it on tracefs because it is a private one. I agreed that. So I think this kind of interface must be managed by BPF subsystem. Is there any API to manage the BPF probe points in BPF subsystem? Thank you, > > -- Steve > > > > > Signed-off-by: Jianlin Lv > > --- > > v2: update commit message > > --- > > Documentation/trace/kprobetrace.rst | 6 +++- > > kernel/trace/trace_dynevent.c | 20 +++++++++++ > > kernel/trace/trace_dynevent.h | 37 ++++++++++++++++++++ > > kernel/trace/trace_kprobe.c | 54 +++++++++++++++++++++++++++++ > > 4 files changed, 116 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst > > index b175d88f31eb..8815d64dd8a6 100644 > > --- a/Documentation/trace/kprobetrace.rst > > +++ b/Documentation/trace/kprobetrace.rst > > @@ -146,7 +146,11 @@ trigger: > > Event Profiling > > --------------- > > You can check the total number of probe hits and probe miss-hits via > > -/sys/kernel/debug/tracing/kprobe_profile. > > +/sys/kernel/debug/tracing/kprobe_profile or > > +/sys/kernel/debug/tracing/kprobe_local_profile. > > +All kprobe events created by kprobe_events will be added to the global > > +list, you can get their profiling via kprobe_profile; kprobe_local_profile > > +shows profiling for private kprobe events created by perf_kprobe pmu. > > The first column is event name, the second is the number of probe hits, > > the third is the number of probe miss-hits. > > > > diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c > > index 076b447a1b88..70ec99cd9c53 100644 > > --- a/kernel/trace/trace_dynevent.c > > +++ b/kernel/trace/trace_dynevent.c > > @@ -181,6 +181,26 @@ static const struct seq_operations dyn_event_seq_op = { > > .show = dyn_event_seq_show > > }; > > > > +#ifdef CONFIG_KPROBE_EVENTS > > +LIST_HEAD(local_event_list); > > + > > +void *local_event_seq_start(struct seq_file *m, loff_t *pos) > > +{ > > + mutex_lock(&event_mutex); > > + return seq_list_start(&local_event_list, *pos); > > +} > > + > > +void *local_event_seq_next(struct seq_file *m, void *v, loff_t *pos) > > +{ > > + return seq_list_next(v, &local_event_list, pos); > > +} > > + > > +void local_event_seq_stop(struct seq_file *m, void *v) > > +{ > > + mutex_unlock(&event_mutex); > > +} > > +#endif /* CONFIG_KPROBE_EVENTS */ > > + > > /* > > * dyn_events_release_all - Release all specific events > > * @type: the dyn_event_operations * which filters releasing events > > diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h > > index 936477a111d3..e30193470295 100644 > > --- a/kernel/trace/trace_dynevent.h > > +++ b/kernel/trace/trace_dynevent.h > > @@ -101,6 +101,43 @@ void dyn_event_seq_stop(struct seq_file *m, void *v); > > int dyn_events_release_all(struct dyn_event_operations *type); > > int dyn_event_release(const char *raw_command, struct dyn_event_operations *type); > > > > +#ifdef CONFIG_KPROBE_EVENTS > > +extern struct list_head local_event_list; > > + > > +static inline > > +int local_event_init(struct dyn_event *ev, struct dyn_event_operations *ops) > > +{ > > + if (!ev || !ops) > > + return -EINVAL; > > + > > + INIT_LIST_HEAD(&ev->list); > > + ev->ops = ops; > > + return 0; > > +} > > + > > +static inline int local_event_add(struct dyn_event *ev) > > +{ > > + lockdep_assert_held(&event_mutex); > > + > > + if (!ev || !ev->ops) > > + return -EINVAL; > > + > > + list_add_tail(&ev->list, &local_event_list); > > + return 0; > > +} > > + > > +static inline void local_event_remove(struct dyn_event *ev) > > +{ > > + lockdep_assert_held(&event_mutex); > > + list_del_init(&ev->list); > > +} > > + > > +void *local_event_seq_start(struct seq_file *m, loff_t *pos); > > +void *local_event_seq_next(struct seq_file *m, void *v, loff_t *pos); > > +void local_event_seq_stop(struct seq_file *m, void *v); > > + > > +#endif /* CONFIG_KPROBE_EVENTS */ > > + > > /* > > * for_each_dyn_event - iterate over the dyn_event list > > * @pos: the struct dyn_event * to use as a loop cursor > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > > index a245ea673715..76f500b17b46 100644 > > --- a/kernel/trace/trace_kprobe.c > > +++ b/kernel/trace/trace_kprobe.c > > @@ -1213,6 +1213,52 @@ static const struct file_operations kprobe_profile_ops = { > > .release = seq_release, > > }; > > > > +#ifdef CONFIG_KPROBE_EVENTS > > +/* kprobe Local profile */ > > +static int local_probes_profile_seq_show(struct seq_file *m, void *v) > > +{ > > + struct dyn_event *ev = v; > > + struct trace_kprobe *tk; > > + > > + if (!is_trace_kprobe(ev)) > > + return 0; > > + > > + tk = to_trace_kprobe(ev); > > + seq_printf(m, " %-44s %15lu %15lu\n", > > + trace_probe_name(&tk->tp), > > + trace_kprobe_nhit(tk), > > + tk->rp.kp.nmissed); > > + > > + return 0; > > +} > > + > > +static const struct seq_operations local_profile_seq_op = { > > + .start = local_event_seq_start, > > + .next = local_event_seq_next, > > + .stop = local_event_seq_stop, > > + .show = local_probes_profile_seq_show > > +}; > > + > > +static int local_profile_open(struct inode *inode, struct file *file) > > +{ > > + int ret; > > + > > + ret = security_locked_down(LOCKDOWN_TRACEFS); > > + if (ret) > > + return ret; > > + > > + return seq_open(file, &local_profile_seq_op); > > +} > > + > > +static const struct file_operations kprobe_local_profile_ops = { > > + .owner = THIS_MODULE, > > + .open = local_profile_open, > > + .read = seq_read, > > + .llseek = seq_lseek, > > + .release = seq_release, > > +}; > > +#endif /* CONFIG_KPROBE_EVENTS */ > > + > > /* Kprobe specific fetch functions */ > > > > /* Return the length of string -- including null terminal byte */ > > @@ -1830,6 +1876,7 @@ create_local_trace_kprobe(char *func, void *addr, unsigned long offs, > > if (ret < 0) > > goto error; > > > > + local_event_add(&tk->devent); > > return trace_probe_event_call(&tk->tp); > > error: > > free_trace_kprobe(tk); > > @@ -1849,6 +1896,7 @@ void destroy_local_trace_kprobe(struct trace_event_call *event_call) > > return; > > } > > > > + local_event_remove(&tk->devent); > > __unregister_trace_kprobe(tk); > > > > free_trace_kprobe(tk); > > @@ -1929,6 +1977,12 @@ static __init int init_kprobe_trace(void) > > trace_create_file("kprobe_profile", TRACE_MODE_READ, > > NULL, NULL, &kprobe_profile_ops); > > > > +#ifdef CONFIG_KPROBE_EVENTS > > + /* kprobe Local profile */ > > + tracefs_create_file("kprobe_local_profile", TRACE_MODE_READ, > > + NULL, NULL, &kprobe_local_profile_ops); > > +#endif /* CONFIG_KPROBE_EVENTS */ > > + > > setup_boot_kprobe_events(); > > > > return 0; > -- Masami Hiramatsu (Google)