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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 90558C2BA19 for ; Tue, 14 Apr 2020 11:12:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B2362072D for ; Tue, 14 Apr 2020 11:12:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390822AbgDNLMa (ORCPT ); Tue, 14 Apr 2020 07:12:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728734AbgDNLMS (ORCPT ); Tue, 14 Apr 2020 07:12:18 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1A42C061A0C; Tue, 14 Apr 2020 04:12:17 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) (envelope-from ) id 1jOIxX-00Gpsu-6e; Tue, 14 Apr 2020 12:38:27 +0200 Message-ID: Subject: Re: WARNING in hwsim_new_radio_nl From: Johannes Berg To: syzbot , davem@davemloft.net, kvalo@codeaurora.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, mathew.j.martineau@linux.intel.com, matthieu.baerts@tessares.net, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Date: Tue, 14 Apr 2020 12:38:22 +0200 In-Reply-To: <000000000000cb517b05a32c917b@google.com> (sfid-20200413_160506_506947_12BA215F) References: <000000000000cb517b05a32c917b@google.com> (sfid-20200413_160506_506947_12BA215F) Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.4 (3.34.4-1.fc31) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi syzbot keepers, On Mon, 2020-04-13 at 07:05 -0700, syzbot wrote: > syzbot has bisected this bug to: > > commit 01cacb00b35cb62b139f07d5f84bcf0eeda8eff6 > Author: Paolo Abeni > Date: Fri Mar 27 21:48:51 2020 +0000 > > mptcp: add netlink-based PM > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10225bb3e00000 This is, fairly obviously, incorrect. Same with the bisection for 6693adf1698864d21734, which is really the same underlying problem as this one (though at a different code site). However, it stands out that this was bisected to a commit that adds a new generic netlink family in both cases. This makes sense - the reproducer identifies the family by *number*, but that number isn't stable, generic netlink families should be identified by *name*. Perhaps somehow syzbot could be taught that, so that the bisection is stable across kernels with different generic netlink families registered? Alternatively, we _could_ add some kind of stable ID mode, but I'm not sure we really want to ... since that would mean people start hardcoding IDs? johannes