From patchwork Wed Mar 23 03:24:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?TWFyay1QSyBUc2FpICjolKHmspvliZsp?= X-Patchwork-Id: 12789413 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 BD6BAC433EF for ; Wed, 23 Mar 2022 03:26:13 +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:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=vXOpKRaobk5iMZgkPReRTt9uAUuyh4pDl+4cXCQ433w=; b=YrwJ7nnRFLyMUo 9n3Ak6I1juUljXpegHDU/pPCCCb8IwEdn3CPeXU8enQVgGhNHWxJCwT1ZCELfG+1Dweufaa6fUXn2 CrAQ1MtX0aaTXiEadIrLTauvetBCezLXjd553KYKaqIJUSSU4+/L3b0zrKstc/XqK9ogO6xasZkMu IElGSTDhprNLCLOBWupuVDXobycc6Gze9KNSPOYSv/VaVGUKrI3BI9DuouZQJ6RsoKdZDplZ5JUjo YIvIfjAh1c+JtoigLqCWzMSyHymdM2fWoQlCWhs9KpqT8bZ9TnTaAfkEgiUHmQcDHbUMkkHzsNFQ1 IzaBwC0ctnl9CzC3qJSQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nWrcM-00Chqj-E4; Wed, 23 Mar 2022 03:25:02 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nWrcI-00ChpR-K4; Wed, 23 Mar 2022 03:25:00 +0000 X-UUID: 7528de70dad24c2cb76fd9c1ec734a0c-20220322 X-UUID: 7528de70dad24c2cb76fd9c1ec734a0c-20220322 Received: from mtkcas68.mediatek.inc [(172.29.94.19)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 450781750; Tue, 22 Mar 2022 20:24:47 -0700 Received: from MTKMBS07N2.mediatek.inc (172.21.101.141) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 22 Mar 2022 20:24:45 -0700 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs07n2.mediatek.inc (172.21.101.141) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 23 Mar 2022 11:24:44 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Wed, 23 Mar 2022 11:24:44 +0800 From: Mark-PK Tsai To: , CC: , , , , , , , , Subject: [PATCH] tracing: Avoid adding duplicated tracer options when update_tracer_options is running in parallel Date: Wed, 23 Mar 2022 11:24:42 +0800 Message-ID: <20220323032442.22082-1-mark-pk.tsai@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20220322133339.GA32582@xsang-OptiPlex-9020> References: <20220322133339.GA32582@xsang-OptiPlex-9020> MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220322_202458_673278_DDDB460A X-CRM114-Status: GOOD ( 12.16 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. 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); __update_tracer_options(tr); + tracer_options_updated = true; mutex_unlock(&trace_types_lock); }