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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6C486C433EF for ; Fri, 22 Apr 2022 21:44:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+sjocIHq5MRhUDxJEtT3ipbCP6Q2LXZWAKCYh55WOyA=; b=klZDaiIOXXRUfs uVafTZVZeYZqnXW1yzL7wOyRCufJoYN6LzNdTLJFkxj5HsKF72JI4bkiRCD7ZH3XNgCduYIt+2ks/ cLG2I5OIl21TQS/HtuIPazrFvKr4GRzmdZ7dHecbv8Rv8J9dUvB5QLb1ItrosW8D5QQdT5MLQx7Tm mEFGSm/uceUls/gnaG3rH/eJQrbSuzATtwGPEjEpbDmSX2IdUz0c8Sg4H4qo36M2ThPCQmZi/zUjJ AqXjLDoPbtnUDyfdYMbaltfyRWaucaFkBUB4tcRoxOMQyKZuC4EJCmdYcRdWAV2w8G6osO3HN+pzC faa5PkhzU45WvV6nVMnA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ni13V-002bPP-E9; Fri, 22 Apr 2022 21:43:09 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ni13R-002bOn-5A; Fri, 22 Apr 2022 21:43:07 +0000 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 A4DD9B83272; Fri, 22 Apr 2022 21:43:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78106C385AA; Fri, 22 Apr 2022 21:43:00 +0000 (UTC) Date: Fri, 22 Apr 2022 17:42:58 -0400 From: Steven Rostedt To: Mark-PK Tsai Cc: , , , , , Subject: Re: [PATCH v3 1/2] tracing: Avoid adding tracer option before update_tracer_options Message-ID: <20220422174258.1f41777a@gandalf.local.home> In-Reply-To: <20220323152257.7871-2-mark-pk.tsai@mediatek.com> References: <20220323152257.7871-1-mark-pk.tsai@mediatek.com> <20220323152257.7871-2-mark-pk.tsai@mediatek.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220422_144305_535192_31993D00 X-CRM114-Status: GOOD ( 21.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 23 Mar 2022 23:22:56 +0800 Mark-PK Tsai wrote: > To prepare for support asynchronous tracer_init_tracefs initcall, > avoid calling create_trace_option_files before __update_tracer_options. > Otherwise, create_trace_option_files will show warning because > some tracers in trace_types list are already in tr->topts. > > For example, hwlat_tracer call register_tracer in late_initcall, > and global_trace.dir is already created in tracing_init_dentry, > hwlat_tracer will be put into tr->topts. > Then if the __update_tracer_options is executed after hwlat_tracer > registered, create_trace_option_files find that hwlat_tracer is > already in tr->topts. > > Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/ > Reported-by: kernel test robot > Signed-off-by: Mark-PK Tsai Before this patch: # ls /sys/kernel/tracing/options annotate funcgraph-duration hex stacktrace bin funcgraph-irqs irq-info sym-addr blk_cgname funcgraph-overhead latency-format sym-offset blk_cgroup funcgraph-overrun markers sym-userobj blk_classic funcgraph-proc overwrite test_nop_accept block funcgraph-tail pause-on-trace test_nop_refuse context-info func-no-repeats printk-msg-only trace_printk disable_on_free func_stack_trace print-parent userstacktrace display-graph function-fork raw verbose event-fork function-trace record-cmd funcgraph-abstime graph-time record-tgid funcgraph-cpu hash-ptr sleep-time After this patch: # ls /sys/kernel/tracing/options annotate disable_on_free irq-info raw trace_printk bin display-graph latency-format record-cmd userstacktrace blk_cgname event-fork markers record-tgid verbose blk_cgroup function-fork overwrite stacktrace blk_classic function-trace pause-on-trace sym-addr block hash-ptr printk-msg-only sym-offset context-info hex print-parent sym-userobj Not good. > --- > kernel/trace/trace.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index eb44418574f9..85ec758c4455 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -6317,12 +6317,18 @@ static void tracing_set_nop(struct trace_array *tr) > tr->current_trace = &nop_trace; > } > > +static bool tracer_options_updated; > + > static void add_tracer_options(struct trace_array *tr, struct tracer *t) > { > /* Only enable if the directory has been created already. */ > if (!tr->dir) > return; > > + /* Only create trace option files after update_tracer_options finish */ > + if (!tracer_options_updated) > + return; > + > create_trace_option_files(tr, t); > } > > @@ -9133,6 +9139,7 @@ static void update_tracer_options(struct trace_array *tr) > { > mutex_lock(&trace_types_lock); > __update_tracer_options(tr); > + tracer_options_updated = true; I think you want to set this before the __update, as doing it after just makes the update a nop. -- Steve > mutex_unlock(&trace_types_lock); > } > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel