From patchwork Wed Oct 28 18:20:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aleksandr Nogikh X-Patchwork-Id: 316147 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9EC38C55179 for ; Wed, 28 Oct 2020 22:16:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 504D624724 for ; Wed, 28 Oct 2020 22:16:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="q4gBqgyl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731405AbgJ1WQU (ORCPT ); Wed, 28 Oct 2020 18:16:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730955AbgJ1WQS (ORCPT ); Wed, 28 Oct 2020 18:16:18 -0400 Received: from mail-ej1-x642.google.com (mail-ej1-x642.google.com [IPv6:2a00:1450:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6684AC0613CF; Wed, 28 Oct 2020 15:16:18 -0700 (PDT) Received: by mail-ej1-x642.google.com with SMTP id s15so1089014ejf.8; Wed, 28 Oct 2020 15:16:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=iwQcabFRrU2vdBHXJKGgczaLWxbb/mobf9EMpVjlwVs=; b=q4gBqgyl5zVnZmWSvnnKZZIJZBciWMboNqlLvxmYb5kZa8bvPbIftieV+ScHhBjPhm ByAXEncuL0uCWZGCidtmsCkx3po0YE/YaMYvR9JKB5DhGuoyEwtnN735wH9U/+NvGRYc kO9yZin0GLhzl6PSgrdiJePNk7uvIF1g1YXAUHNmrdVWXlccVzuV/35sxiPgYzAsWJk2 VH+QX+G52kaRNKUI0LGpFnWnKEuc4fy8sYcA+fcngqyHvy7DpHPFlFMNkkk715GFsgCN b9TkGrbvI6iKisjZKI7ESZtQlZ3nAD0QXKtP0It9YKJdkznrGKijH6EuOHk0cERtgn43 e9bw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=iwQcabFRrU2vdBHXJKGgczaLWxbb/mobf9EMpVjlwVs=; b=cfqjka4S6GZZ10IYcrub9wZ0rTComV5mW6gOgxWja/FfWRyq2gXEOueyiGuAD5wjMl DjORAkX2epfGlbwNKLoSDxCuEYE8aRlX37MPuqM1DqJgadBDEULqjlTgth6Ir8trhcH5 +R/bnXruxFZs8HnZmSDzlqdA4sBwxpwHIQVldoBKDjy+UUkKeHO2rslO0T20KaPmgNy1 A5pXXOhoqTR+T1/n1K++xjBtbXLcmpneMXqDrOtnvk8nKyozxVX82v1+1BfWYz64Bf76 QUEEC+NjnJLDVe5Mxtvd0yIIz83mQUZ8NwvRVIiVkuSRod2FgEXeAB0/64H5yaZkdN3h pqMQ== X-Gm-Message-State: AOAM531N/IU6UtV+xCRiZuW4qJz82JChyN++59cnDt/6PXkNH2t0PxjT whuJT11egEj4dIrZGEXn6wv5zijsrprF9A== X-Google-Smtp-Source: ABdhPJyx/Tg3lpa91puNZ1/K/FVLjX3eAERpw3U7g9z2MqebNiUdnJ6XKDNtvID/bAL78uck3RiTLA== X-Received: by 2002:a5d:55c8:: with SMTP id i8mr687366wrw.194.1603909263036; Wed, 28 Oct 2020 11:21:03 -0700 (PDT) Received: from nogikh.c.googlers.com.com (88.140.78.34.bc.googleusercontent.com. [34.78.140.88]) by smtp.gmail.com with ESMTPSA id r28sm531178wrr.81.2020.10.28.11.21.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Oct 2020 11:21:02 -0700 (PDT) From: Aleksandr Nogikh To: davem@davemloft.net, kuba@kernel.org, johannes@sipsolutions.net Cc: edumazet@google.com, andreyknvl@google.com, dvyukov@google.com, elver@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, willemdebruijn.kernel@gmail.com, Aleksandr Nogikh Subject: [PATCH v4 1/3] kernel: make kcov_common_handle consider the current context Date: Wed, 28 Oct 2020 18:20:16 +0000 Message-Id: <20201028182018.1780842-2-aleksandrnogikh@gmail.com> X-Mailer: git-send-email 2.29.0.rc2.309.g374f81d7ae-goog In-Reply-To: <20201028182018.1780842-1-aleksandrnogikh@gmail.com> References: <20201028182018.1780842-1-aleksandrnogikh@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Aleksandr Nogikh kcov_common_handle is a method that is used to obtain a "default" KCOV remote handle of the current process. The handle can later be passed to kcov_remote_start in order to collect coverage for the processing that is initiated by one process, but done in another. For details see Documentation/dev-tools/kcov.rst and comments in kernel/kcov.c. Presently, if kcov_common_handle is called in an IRQ context, it will return a handle for the interrupted process. This may lead to unreliable and incorrect coverage collection. Adjust the behavior of kcov_common_handle in the following way. If it is called in a task context, return the common handle for the currently running task. Otherwise, return 0. Signed-off-by: Aleksandr Nogikh Reviewed-by: Andrey Konovalov --- kernel/kcov.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/kcov.c b/kernel/kcov.c index 6b8368be89c8..80bfe71bbe13 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -1023,6 +1023,8 @@ EXPORT_SYMBOL(kcov_remote_stop); /* See the comment before kcov_remote_start() for usage details. */ u64 kcov_common_handle(void) { + if (!in_task()) + return 0; return current->kcov_handle; } EXPORT_SYMBOL(kcov_common_handle);