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 X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 7DBBAC43219 for ; Tue, 30 Apr 2019 21:25:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3EC6721743 for ; Tue, 30 Apr 2019 21:25:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sl0AarRP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727327AbfD3VZE (ORCPT ); Tue, 30 Apr 2019 17:25:04 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:35862 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726048AbfD3VZD (ORCPT ); Tue, 30 Apr 2019 17:25:03 -0400 Received: by mail-pl1-f196.google.com with SMTP id w20so6707051plq.3; Tue, 30 Apr 2019 14:25:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Zw93kVo3Zfkf7gA3YeXj6RSgg5k0vIjqnM2DvtbZHAI=; b=sl0AarRP1TsvqN4lIwtjAb0B7biXJtnSNV8bx8FXEYhSEVymQc0Bxt+S0pI62T/gGo UrlqSLPeDYFLsnniqZnzOvn8n9Mns2rYJshQy8w3iWdy1LDPahYAKDHNJVTkZpDMhWTG Yn2cSsbdygxsKI4OzWXA0V58tU3zeE4oUTiPenk+x8wD0+dAy7PhWBuC/Eh7TSvUnMdu pgd1yT7EXyORAAh0hdDdesfLe2EhRT1+rwQ4iyJnXehq3RNXyyiy+kjNy8QYsGeAhkz1 TjHdKzY0q1Xtn1NAtFgyktwrDYG5RQozIBXE7po/5MQx3ShjVvEZkJj2SZOCwwwEfit+ S8Cg== 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=Zw93kVo3Zfkf7gA3YeXj6RSgg5k0vIjqnM2DvtbZHAI=; b=ckD3PEqG7LBDVwo+53uBdrUbHuvrBpBZKHxJwSP26GhUFy3REXmdarxSmF1X507/oz ZAIJkCyBVhA/yP8S9yE3pUjHAg5TYlmocqFjBmwLlja/B7XDpGGBWPJZwPXPojKDbB2F dUe0oetqDDOSmd77j/0lZCeaofMVuDZWQRfaFjOyBBS2s+DuWDOwtGb4YQT+R3CKhL+/ YMRadYJN6TL5LcrtwTR8rakZWjBtkYPzBOpMzN9DMTRDhNh2ZfEk4/tYVb1OLClXLpI4 GWvncxh30Ugc0GGQskEmXNbrcQIUCQjPGl26KBxrTeuZ29kqGoBFp+NJ43G+q+DDaVUf if6A== X-Gm-Message-State: APjAAAVmocpvt/OG/kuE7fMU5GtlCW2VG5eW6kzQz+I1dBmpnaeJqzbF SQWLRAsK9KQ549gujz5X7F6yrhyHwOQWHE03Lsk8LFYj X-Google-Smtp-Source: APXvYqxPDZtFpO+c7rNvc+k762smiJY4RzJneujKOPsKuF9emm+FzXjVhnEMgIQjRUzdONAxVuppQ5NJ4a2hctrRhOA= X-Received: by 2002:a17:902:9b8d:: with SMTP id y13mr17753012plp.70.1556659502588; Tue, 30 Apr 2019 14:25:02 -0700 (PDT) MIME-Version: 1.0 References: <20190429173805.4455-1-mcroce@redhat.com> In-Reply-To: <20190429173805.4455-1-mcroce@redhat.com> From: Cong Wang Date: Tue, 30 Apr 2019 14:24:51 -0700 Message-ID: Subject: Re: [PATCH net] cls_matchall: avoid panic when receiving a packet before filter set To: Matteo Croce Cc: Linux Kernel Network Developers , LKML , Jamal Hadi Salim , Jiri Pirko , "David S. Miller" 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 Mon, Apr 29, 2019 at 10:38 AM Matteo Croce wrote: > > When a matchall classifier is added, there is a small time interval in > which tp->root is NULL. If we receive a packet in this small time slice > a NULL pointer dereference will happen, leading to a kernel panic: Hmm, why not just check tp->root against NULL in mall_classify()? Also, which is the offending commit here? Please add a Fixes: tag. Thanks.