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 77C2CC433EF for ; Wed, 23 Mar 2022 13:30:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244290AbiCWNb7 (ORCPT ); Wed, 23 Mar 2022 09:31:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236476AbiCWNb4 (ORCPT ); Wed, 23 Mar 2022 09:31:56 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 015BD75C2C for ; Wed, 23 Mar 2022 06:30:26 -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 77E1FB81EDB for ; Wed, 23 Mar 2022 13:30:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AD98C340E8; Wed, 23 Mar 2022 13:30:22 +0000 (UTC) Date: Wed, 23 Mar 2022 09:30:21 -0400 From: Steven Rostedt To: Mark-PK Tsai Cc: , , , , , , , , Subject: Re: [PATCH] tracing: Avoid adding duplicated tracer options when update_tracer_options is running in parallel Message-ID: <20220323093021.4f541b40@gandalf.local.home> In-Reply-To: <20220323032442.22082-1-mark-pk.tsai@mediatek.com> References: <20220322133339.GA32582@xsang-OptiPlex-9020> <20220323032442.22082-1-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 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 23 Mar 2022 11:24:42 +0800 Mark-PK Tsai wrote: > When update_tracer_options is running in parallel, > tr->tops might be updated before the trace_types list traversal. > Let update_tracer_options traverse the trace_types list safely in > kernel init time and avoid the tr->tops update before it finish. ??? Have you seen a bug here? I'm totally confused by this. > > Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/ > Reported-by: kernel test robot > Signed-off-by: Mark-PK Tsai > --- > kernel/trace/trace.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index adb37e437a05..2974ae056068 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); How is update_trace_options run in parallel? There's a mutex that protects it. -- Steve > __update_tracer_options(tr); > + tracer_options_updated = true; > mutex_unlock(&trace_types_lock); > } > 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 57F41C433EF for ; Wed, 23 Mar 2022 13:30:43 +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=KES53LvAlRKSvvdh5Ef64jZYjv+1cdsYfVpysD2ucSQ=; b=HxXU/Perq3Rwb2 L72/Y8KjfdRy30lM7Nh4H9EZc0d9co2lFRcdaEtHc00xYsEmNCkxlodFtX+AfjedVhTs3bpIYkRWH a6VMFZH3lDoFqXe6KD8s+bGDg9d6/g/oRab8QD+N+0w1P5qOiTjKZRQUoyAP1OnGYtJeVG+rL0unp Ci7AQRQ3/AYXoq2hDCnIKCVoVXJmzngLmiWP8zrU7X+8drSDBOhks7D5PD1o+CttGEjcytD37khqK r7EZESzdJojhKQbqeteHPmplzNo4dCWmxRQRbcZQh4ZPfijOrDSrYwCga6W4+dUObJI4xo5RFJx9P WUivhQyjMHpTZ/1pq0+A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nX14P-00DjJW-5i; Wed, 23 Mar 2022 13:30:37 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nX14D-00DjHF-5z; Wed, 23 Mar 2022 13:30:26 +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 dfw.source.kernel.org (Postfix) with ESMTPS id AB5B66163B; Wed, 23 Mar 2022 13:30:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AD98C340E8; Wed, 23 Mar 2022 13:30:22 +0000 (UTC) Date: Wed, 23 Mar 2022 09:30:21 -0400 From: Steven Rostedt To: Mark-PK Tsai Cc: , , , , , , , , Subject: Re: [PATCH] tracing: Avoid adding duplicated tracer options when update_tracer_options is running in parallel Message-ID: <20220323093021.4f541b40@gandalf.local.home> In-Reply-To: <20220323032442.22082-1-mark-pk.tsai@mediatek.com> References: <20220322133339.GA32582@xsang-OptiPlex-9020> <20220323032442.22082-1-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-20220323_063025_300439_0ACB6C43 X-CRM114-Status: GOOD ( 21.37 ) X-BeenThere: linux-mediatek@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-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Wed, 23 Mar 2022 11:24:42 +0800 Mark-PK Tsai wrote: > When update_tracer_options is running in parallel, > tr->tops might be updated before the trace_types list traversal. > Let update_tracer_options traverse the trace_types list safely in > kernel init time and avoid the tr->tops update before it finish. ??? Have you seen a bug here? I'm totally confused by this. > > Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/ > Reported-by: kernel test robot > Signed-off-by: Mark-PK Tsai > --- > kernel/trace/trace.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index adb37e437a05..2974ae056068 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); How is update_trace_options run in parallel? There's a mutex that protects it. -- Steve > __update_tracer_options(tr); > + tracer_options_updated = true; > mutex_unlock(&trace_types_lock); > } > _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek 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 A26D3C433EF for ; Wed, 23 Mar 2022 13:31:43 +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=KsKRkO0g5BI6m/TAYAPLjO2z2U1z7JMRW351UVI5qdM=; b=VQAsiXihgaUaDQ ckBXIC+SIJUOEocnk+eLyeuxYSIXZLizORyFm7suGI9Pk9KA1HXDloA5hTPREgBOetCL2OSvp8//f w+cBcvJ8PJaBeQN/F/TkNT8olaeQcU0C/2FkHbE8q03MsXZmQCCEyA4FsPcSsDDJMi8y/U548KgJV Ncqijxs3Y6lDGTtJBDCU99dUdZmMnzmPdNYvBfrXSbjYze0f//vrFVoF+/CVc8uXVeVOeN5owzW/7 py53y3MXy4QbuvKc/n9EBrGcKkm7JRvqez39mafjjf2ax8nEV9O0Zke1rzeiO0Ttlfkm1B5RRKyco 2WCNqieP5zJfjvq2XH1w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nX14G-00DjHs-So; Wed, 23 Mar 2022 13:30:28 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nX14D-00DjHF-5z; Wed, 23 Mar 2022 13:30:26 +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 dfw.source.kernel.org (Postfix) with ESMTPS id AB5B66163B; Wed, 23 Mar 2022 13:30:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AD98C340E8; Wed, 23 Mar 2022 13:30:22 +0000 (UTC) Date: Wed, 23 Mar 2022 09:30:21 -0400 From: Steven Rostedt To: Mark-PK Tsai Cc: , , , , , , , , Subject: Re: [PATCH] tracing: Avoid adding duplicated tracer options when update_tracer_options is running in parallel Message-ID: <20220323093021.4f541b40@gandalf.local.home> In-Reply-To: <20220323032442.22082-1-mark-pk.tsai@mediatek.com> References: <20220322133339.GA32582@xsang-OptiPlex-9020> <20220323032442.22082-1-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-20220323_063025_300439_0ACB6C43 X-CRM114-Status: GOOD ( 21.37 ) 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 11:24:42 +0800 Mark-PK Tsai wrote: > When update_tracer_options is running in parallel, > tr->tops might be updated before the trace_types list traversal. > Let update_tracer_options traverse the trace_types list safely in > kernel init time and avoid the tr->tops update before it finish. ??? Have you seen a bug here? I'm totally confused by this. > > Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/ > Reported-by: kernel test robot > Signed-off-by: Mark-PK Tsai > --- > kernel/trace/trace.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index adb37e437a05..2974ae056068 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); How is update_trace_options run in parallel? There's a mutex that protects it. -- Steve > __update_tracer_options(tr); > + tracer_options_updated = true; > 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============8065524399261978805==" MIME-Version: 1.0 From: Steven Rostedt To: lkp@lists.01.org Subject: Re: [PATCH] tracing: Avoid adding duplicated tracer options when update_tracer_options is running in parallel Date: Wed, 23 Mar 2022 09:30:21 -0400 Message-ID: <20220323093021.4f541b40@gandalf.local.home> In-Reply-To: <20220323032442.22082-1-mark-pk.tsai@mediatek.com> List-Id: --===============8065524399261978805== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Wed, 23 Mar 2022 11:24:42 +0800 Mark-PK Tsai wrote: > When update_tracer_options is running in parallel, > tr->tops might be updated before the trace_types list traversal. > Let update_tracer_options traverse the trace_types list safely in > kernel init time and avoid the tr->tops update before it finish. ??? Have you seen a bug here? I'm totally confused by this. > = > Link: https://lore.kernel.org/lkml/20220322133339.GA32582(a)xsang-OptiPle= x-9020/ > Reported-by: kernel test robot > Signed-off-by: Mark-PK Tsai > --- > kernel/trace/trace.c | 7 +++++++ > 1 file changed, 7 insertions(+) > = > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index adb37e437a05..2974ae056068 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -6317,12 +6317,18 @@ static void tracing_set_nop(struct trace_array *t= r) > tr->current_trace =3D &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_arra= y *tr) > { > mutex_lock(&trace_types_lock); How is update_trace_options run in parallel? There's a mutex that protects it. = -- Steve > __update_tracer_options(tr); > + tracer_options_updated =3D true; > mutex_unlock(&trace_types_lock); > } > =20 --===============8065524399261978805==--