Received: by 2002:a05:6902:102b:0:0:0:0 with SMTP id x11csp701014ybt; Fri, 19 Jun 2020 11:25:48 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwSl2WrVSdPYNTlN/4pHyhBIm11IPYJ/QLe77LSb3v5ggHATznJahA0PmhVDp9ACM/YSMDq X-Received: by 2002:a17:906:3951:: with SMTP id g17mr5006977eje.414.1592591148408; Fri, 19 Jun 2020 11:25:48 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1592591148; cv=none; d=google.com; s=arc-20160816; b=KsQlz6OSnViMAxLbgZFD4R+Mu7QeZvD/13UzkzfcBdPZncBOwEb0dqkqpXmslibt6w 6xmKKv8F9UwrZKpd/rE2c9wQrAx80SYDlruIXFPUvUzRVqLbO6BsrdYnRUMacp+WDq38 RHUNocvlejIDxwUVK3aetzuGa+WcLMKzCJQn76VKncAP1zlQTqk3XXFWLnSFxDzyd3Cd AmeTtgQkuC/kWx6yxDsyac15X4lHcO5xVtkWaM6/an+mYD1Q0tveRtm9/R4cBkwtQ0u8 YAxLetDVAVetfH8C502y+KU+WGhgT5rcRzmtS+WZx0bpUgfWcIUv0SlkiJV0Wjhjf6lW DrmQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version; bh=/6fVd8/rN7MHG3zvTKeKPFhmmlDHpXzdpSC6EWMceGA=; b=jJiJmq7PmhQOA9GwL5IQXxYEuslF847FNnOLaMnUYlQpMeajovUD+qBp/IhvMqzyGG +hF+TE9dxhAlVC5GDYeapLdg5TROORiiVWxf3rMf70rE8Zdiz7qhEZTRyOQGYY/itbcx jnkgir4ufzvvv45ou/hkJdBS9+qayx56bd1YGf1OIKia0QhzY/Tu6fuLKTUixIoch9VD uuIBGWqqu68sjhMS6SkbS3+mYsHU3I+SPSwGehtkbi16wuw8T5sicDYYO4RLkc7MeknU IBrnl0fmkgzCOM8bbDe+4T7ySZgkFJyKQvHos2OvH8oz9JcB2YbNYGQmU7TpNwfRZpuh 9deg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id c22si5056218edx.584.2020.06.19.11.25.25; Fri, 19 Jun 2020 11:25:48 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732406AbgFSNNL (ORCPT + 99 others); Fri, 19 Jun 2020 09:13:11 -0400 Received: from mail-wr1-f45.google.com ([209.85.221.45]:44782 "EHLO mail-wr1-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726124AbgFSNNJ (ORCPT ); Fri, 19 Jun 2020 09:13:09 -0400 Received: by mail-wr1-f45.google.com with SMTP id b6so9632721wrs.11 for ; Fri, 19 Jun 2020 06:13:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=/6fVd8/rN7MHG3zvTKeKPFhmmlDHpXzdpSC6EWMceGA=; b=YgFrALzvWPPR5N8dBOhzkJLFa2XbSSisPrLpP/0Zf6BdCgAUmMFMwLcr65kMs6spth Fswxb9UxEXhxKd68P/6JmARfBXIGlwxGjoonIhJuC+XOZkCBQv7DpFigT819yIh3WDXU a2pbjrT1BkLqO1YcIUVxJBroFv8dhZSKAUv3XrPs15ZE797nnoqVv88cDIhJKSIhHEgA E8dAMDoT5EzUfJuGEa+86sWTpMQJVWBKtq9RoMzLzQdPLoUrv2BsKjH2lymOuqz/SLNL 3zhYKfO92mqixWqPN6wl3OJRCsUk1CfGpihD3IZLKJZW6F6BtcJBtdeTiPzLafyIOwkq GnMQ== X-Gm-Message-State: AOAM531c2BhUHgVFa0GaDoCNMASBCM8PQnA/TJZAJelJtgamlEyV0Jgv /zP/21AWVT1QdHkfYtBNFC1eVhx7y4ZWP3KzDFk= X-Received: by 2002:a5d:428e:: with SMTP id k14mr4072363wrq.21.1592572387702; Fri, 19 Jun 2020 06:13:07 -0700 (PDT) MIME-Version: 1.0 References: <20200618003916.26644-1-gaurav1086@gmail.com> In-Reply-To: From: Namhyung Kim Date: Fri, 19 Jun 2020 22:12:56 +0900 Message-ID: Subject: Re: [PATCH] [perf] Fix null pointer deference in nest_epollfd To: gaurav singh Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Tommi Rantala , Thomas Gleixner , "open list:PERFORMANCE EVENTS SUBSYSTEM" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 19, 2020 at 6:28 AM gaurav singh wrote: > > multiqu is a static bool which is never assigned and nested is a static int (=0) It's set by command line option (-m). Thanks Namhyung > and only assigned in nest_epollfd(). Hence, > > if (nested) > nest_epollfd(NULL); > > probably never gets executed.