From patchwork Wed Nov 25 16:24:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marco Elver X-Patchwork-Id: 11931493 X-Patchwork-Delegate: kuba@kernel.org 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 7AC79C56202 for ; Wed, 25 Nov 2020 16:26:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21FB22067C for ; Wed, 25 Nov 2020 16:26:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rWRgvVMR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731279AbgKYQZh (ORCPT ); Wed, 25 Nov 2020 11:25:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731278AbgKYQZg (ORCPT ); Wed, 25 Nov 2020 11:25:36 -0500 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 006BEC0613D4 for ; Wed, 25 Nov 2020 08:25:34 -0800 (PST) Received: by mail-qt1-x84a.google.com with SMTP id v18so2873463qta.22 for ; Wed, 25 Nov 2020 08:25:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=no14nsVrqsySIKMLKuU/qBvlepwoMcLT6bSb3aZ/zhU=; b=rWRgvVMRO0CUdSU8Qv6si89hg0Ryx3BuzihRsJ47u3eFHN8LYh1Vimv5hzKVIwnCqu hHhZEMEXKzGG/6J9hRmAJVMlXv5ERrjFKOqHUIWCBPxIOC5mMwmJN7H3QOdxhNhXt/VG swcel8subQcvBB0Ej7qrbBhkiQBH/sZh1ylx9CT/o+cHUBSVen4/G7AW4d0ZP4gAupNF GqznoVtIWOHcm2ca8N8iz76MbpBV0CFtTxxNnNcwNxqia8ObmOjFgf003lx3zUP830e/ Nu1jK/dza8+Ye+jjP5SEZn8F6YaAt8+EVvEMW2z4psRxqi730nD8nOtoF7k6wCp9+T9d FTXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=no14nsVrqsySIKMLKuU/qBvlepwoMcLT6bSb3aZ/zhU=; b=aF1Zp5GSKop4/e615JdMYkZ2GWb3bwnXBHmACNaJtNH8g8Dw1NKYBNbns/UN9zMqQc eUsEK5tfr4Pljp7Z9PsxNhbqLyUwNzoGCLEqOkP3Zem2FSrXzat7lmmV2ZF113oQeox9 /LOzz6UNIjzbDL/MTUS1Ywxoyq5WFeJYkq2sHtDN4ho+ejooM9EMflyB7ab2NQ2q1wX1 anh+6Ivp8j/43h9Xx3H0uX3YzO5mA2/W1Vz5dWMkX9VnNtJqBkilPFfhMYUttaj3jrgB P7EVlnHdJd9AKHGKapIfiolvnxOStUp5WjJiLWOnnLFaOWtaaN21B7QFOJDPsXnCdbjh Xa0A== X-Gm-Message-State: AOAM5300L8v94Ee3kd+ruuWLBDmWUJ8ZHjVenPJJWLtKp/izTTGIhLvd bI9DBphF8+JHf7igqVNyNDIslI6R6g== X-Google-Smtp-Source: ABdhPJwCorX1KcHgm8LwihXrhAXtD9W3r7tduUqpOGEG1WJrDpd4LRl0b77lMC8XFLcOsbys4kX3bWoDwQ== Sender: "elver via sendgmr" X-Received: from elver.muc.corp.google.com ([2a00:79e0:15:13:f693:9fff:fef4:2449]) (user=elver job=sendgmr) by 2002:a0c:e9c7:: with SMTP id q7mr4494432qvo.9.1606321534107; Wed, 25 Nov 2020 08:25:34 -0800 (PST) Date: Wed, 25 Nov 2020 17:24:53 +0100 In-Reply-To: <20201125162455.1690502-1-elver@google.com> Message-Id: <20201125162455.1690502-2-elver@google.com> Mime-Version: 1.0 References: <20201125162455.1690502-1-elver@google.com> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH v6 1/3] kernel: make kcov_common_handle consider the current context From: Marco Elver To: elver@google.com, davem@davemloft.net, kuba@kernel.org, johannes@sipsolutions.net Cc: akpm@linux-foundation.org, a.nogikh@gmail.com, edumazet@google.com, andreyknvl@google.com, dvyukov@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, idosch@idosch.org, fw@strlen.de, willemb@google.com, Aleksandr Nogikh 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 Signed-off-by: Marco Elver 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);