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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 63277C18E5A for ; Tue, 10 Mar 2020 16:01:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D89021D56 for ; Tue, 10 Mar 2020 16:01:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="QYDxC/nu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726801AbgCJQBW (ORCPT ); Tue, 10 Mar 2020 12:01:22 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:36662 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726674AbgCJQBV (ORCPT ); Tue, 10 Mar 2020 12:01:21 -0400 Received: by mail-pl1-f195.google.com with SMTP id g12so5604326plo.3 for ; Tue, 10 Mar 2020 09:01:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=5PprlbqoqI+8cqH5y1+LaXm/Lh1O+UbpqxwQEoE+kVQ=; b=QYDxC/nug0FPO0R2YDDHDpINh+3k13f/K2ZFHSvhTtDb+xxhNyCFtyrpCsUQy1dWvN GCiI4tkRZEnq/U0iMzpS8zQEPBFV0kTt0Cmo90IelMR3bgcbMzIow1xlr6OhlTUMgYEd ZfMxcAxoXjw/IMN7D8O9LQ2cZRfgF/iSJRu4g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=5PprlbqoqI+8cqH5y1+LaXm/Lh1O+UbpqxwQEoE+kVQ=; b=eIe+5C3dFcWR82gukrn0cFn8Ho8sMmZ9BlB23KF3+0ljeYOx4vIE+1AMdd3LGY1BAO NVuJ5MOdIcfyaxLNdTuYThZw+EIaJXOlXqow0+lVM6+TGUu2drJrbswu3F3VZo1EGEg5 c/f0lED2IZmGvHXteDBIG3nybGj9v/MeBGFmKIKPO1PASHK50fwzBsQ9UYRbImOua75P DoOsgj4TgxGrKsyTfQbukIlszDgHlHZ9LIGvsF1H3AWJh/AAtUfe7tCUSLX2HraP1MYi RMEX7DXSekwDUZ01ho6DOkJ2iWA7/T0xXp94W2lCvHRY9Z3dvwEtKjXPOs/aANejHIoF HpIw== X-Gm-Message-State: ANhLgQ3IORScKImXV/5cbM4M/+PrV+IneF0rDC3KbfzzuiVd9mzeYgMk th+yskKqh2GvAHZC0JsohlwKeQ== X-Google-Smtp-Source: ADFU+vtmM+D+yGWVPf1IZeuUEbx/otAbFEt5GhAZoqGWcLN6EsWZZ4nPx3ClLaNnJpKVk5Q1kJWBww== X-Received: by 2002:a17:902:b903:: with SMTP id bf3mr21622900plb.144.1583856080398; Tue, 10 Mar 2020 09:01:20 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id 6sm7318987pfx.69.2020.03.10.09.01.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Mar 2020 09:01:19 -0700 (PDT) Date: Tue, 10 Mar 2020 09:01:18 -0700 From: Kees Cook To: syzbot Cc: ardb@kernel.org, davem@davemloft.net, guohanjun@huawei.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-sctp@vger.kernel.org, marcelo.leitner@gmail.com, mingo@kernel.org, netdev@vger.kernel.org, nhorman@tuxdriver.com, syzkaller-bugs@googlegroups.com, vyasevich@gmail.com, will@kernel.org Subject: Re: WARNING: refcount bug in sctp_wfree Message-ID: <202003100900.1E2E399@keescook> References: <00000000000088452f05a07621d2@google.com> <000000000000cc985b05a07ce36f@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000cc985b05a07ce36f@google.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Mar 10, 2020 at 02:39:01AM -0700, syzbot wrote: > syzbot has bisected this bug to: > > commit fb041bb7c0a918b95c6889fc965cdc4a75b4c0ca > Author: Will Deacon > Date: Thu Nov 21 11:59:00 2019 +0000 > > locking/refcount: Consolidate implementations of refcount_t I suspect this is just bisecting to here because it made the refcount checks more strict? -Kees > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=117e9e91e00000 > start commit: 2c523b34 Linux 5.6-rc5 > git tree: upstream > final crash: https://syzkaller.appspot.com/x/report.txt?x=137e9e91e00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=157e9e91e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=a5295e161cd85b82 > dashboard link: https://syzkaller.appspot.com/bug?extid=cea71eec5d6de256d54d > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164b5181e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=166dd70de00000 > > Reported-by: syzbot+cea71eec5d6de256d54d@syzkaller.appspotmail.com > Fixes: fb041bb7c0a9 ("locking/refcount: Consolidate implementations of refcount_t") > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection -- Kees Cook