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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8FBAEB64DD for ; Thu, 20 Jul 2023 07:19:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231303AbjGTHTs (ORCPT ); Thu, 20 Jul 2023 03:19:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231359AbjGTHTn (ORCPT ); Thu, 20 Jul 2023 03:19:43 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5F2919A6 for ; Thu, 20 Jul 2023 00:18:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689837531; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bYGtszuU5wIRpPGldAIwvzXGaeXBUQT3e9Yc1Tmh1Tk=; b=Z9pGKg/KsTeZ5EcdTMu2Fldfe2m7ybWbYmiCAbDbu4wtqbcf2MB2XL7G+f/6JuhdHO0zc6 xafnAB7qS3DtdhJdlHNLyqs+06YHO0Es8kWiyiz22U/96EYeiN9FxxhTr5iuJI9tLVi2l4 D97gnJo5AvnFSYesupbb0DiM/GRkG60= Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-445-JJ8ro4jVPTGsDKyHs2dzvQ-1; Thu, 20 Jul 2023 03:18:50 -0400 X-MC-Unique: JJ8ro4jVPTGsDKyHs2dzvQ-1 Received: by mail-qk1-f197.google.com with SMTP id af79cd13be357-767edbf73cbso13955385a.1 for ; Thu, 20 Jul 2023 00:18:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689837530; x=1690442330; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=bYGtszuU5wIRpPGldAIwvzXGaeXBUQT3e9Yc1Tmh1Tk=; b=QndsRujp34H8EMGrV27+VLYFaDxsLnxZ8t7Wt856at08+EJH/HEy3Ckzm+cHZof/1G uXGX5DuousB4969/UjzHMlb6AhIV0uUV4JfJ8wSPAlXZNqx/A7CwoY0FQ2p6oINeQ1K0 ZvPACuTPLs7k+w4Gvu0YwQL44PxwZWao0UfQHUCuNdp9vYWHUI2YPCZd+XK7Id+uXkWc AT7RG9apStPNFsUwDfzXDc/SE5Ucayk8owZXbcwxXy4QTs1Cbmjs9thFLPZdF6XCJa2h /lgwEi/ujtWzxMpB8JQQ/c08byUnzjDovCSo+cArp0wh97ayks7bYqr9gUN5D+H26ys5 Q/kw== X-Gm-Message-State: ABy/qLaeF5iV9UNV6eiR1ZdLEamLR2kIIsj/FTHUFNuINL6jWx7lMlzb r6wwR7/VUVqoGh1TIM6DzKgjh1Awv5X3yogaiPi3pwgqLzT5hPpsBfQPnZQ7fsdI3YaIrSCPNk1 Us4uY1fI5OAMWMkTKOu7O8G8= X-Received: by 2002:a05:6214:762:b0:616:870c:96b8 with SMTP id f2-20020a056214076200b00616870c96b8mr17420017qvz.3.1689837530202; Thu, 20 Jul 2023 00:18:50 -0700 (PDT) X-Google-Smtp-Source: APBJJlFNH0y5bvIQeSocI2GpS8aKw2ULselhDKyztO/OsqWZvlAvU9rCW8Bzkmb5n6WaEJyCUMCrhw== X-Received: by 2002:a05:6214:762:b0:616:870c:96b8 with SMTP id f2-20020a056214076200b00616870c96b8mr17419995qvz.3.1689837529948; Thu, 20 Jul 2023 00:18:49 -0700 (PDT) Received: from gerbillo.redhat.com (146-241-226-170.dyn.eolo.it. [146.241.226.170]) by smtp.gmail.com with ESMTPSA id n14-20020a0ce48e000000b0062b76c29978sm154802qvl.6.2023.07.20.00.18.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Jul 2023 00:18:49 -0700 (PDT) Message-ID: Subject: Re: [syzbot] [btrfs?] [netfilter?] BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! (2) From: Paolo Abeni To: Jakub Kicinski , netdev@vger.kernel.org Cc: Florian Westphal , Aleksandr Nogikh , syzbot , dsterba@suse.cz, bakmitopiacibubur@boga.indosterling.com, clm@fb.com, davem@davemloft.net, dsahern@kernel.org, dsterba@suse.com, gregkh@linuxfoundation.org, jirislaby@kernel.org, josef@toxicpanda.com, kadlec@netfilter.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux@armlinux.org.uk, netfilter-devel@vger.kernel.org, pablo@netfilter.org, syzkaller-bugs@googlegroups.com Date: Thu, 20 Jul 2023 09:18:44 +0200 In-Reply-To: <20230719203030.1296596a@kernel.org> References: <20230719170446.GR20457@twin.jikos.cz> <00000000000042a3ac0600da1f69@google.com> <20230719231207.GF32192@breakpoint.cc> <20230719203030.1296596a@kernel.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.4 (3.46.4-1.fc37) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Wed, 2023-07-19 at 20:30 -0700, Jakub Kicinski wrote: > On Thu, 20 Jul 2023 01:12:07 +0200 Florian Westphal wrote: > > I don't see any netfilter involvement here. > >=20 > > The repro just creates a massive amount of team devices. > >=20 > > At the time it hits the LOCKDEP limits on my test vm it has > > created ~2k team devices, system load is at +14 because udev > > is also busy spawing hotplug scripts for the new devices. > >=20 > > After reboot and suspending the running reproducer after about 1500 > > devices (before hitting lockdep limits), followed by 'ip link del' for > > the team devices gets the lockdep entries down to ~8k (from 40k), > > which is in the range that it has on this VM after a fresh boot. > >=20 > > So as far as I can see this workload is just pushing lockdep > > past what it can handle with the configured settings and is > > not triggering any actual bug. >=20 > The lockdep splat because of netdevice stacking is one of our top > reports from syzbot. Is anyone else feeling like we should add=20 > an artificial but very high limit on netdev stacking? :( We already have a similar limit for xmit: XMIT_RECURSION_LIMIT. I guess stacking more then such devices will be quite useless/non functional. We could use such value to limit the device stacking, too. Cheers, Paolo