From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D216171A4 for ; Thu, 20 Jul 2023 07:18:54 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEA9F19A4 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=1689837532; 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=VfWerjhVrq3SqJPb78ypstiUCvDKGFZN6+DRfG3QZS+m22Krf/A86latEQkHRBzi6gL/x0 Wd5LsBdxoQrmkzCVaEgpzYVtEaPIgcNuuuBXKj62f5ekEybYv08JATL5myzq8Em+PFksEH MY+QFxj4X7EXO/CNwlF4pHZAF2GHWsM= Received: from mail-qv1-f70.google.com (mail-qv1-f70.google.com [209.85.219.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-490-EhmXaa4gO4mXJZ3phK_0vA-1; Thu, 20 Jul 2023 03:18:50 -0400 X-MC-Unique: EhmXaa4gO4mXJZ3phK_0vA-1 Received: by mail-qv1-f70.google.com with SMTP id 6a1803df08f44-639ae879810so1457976d6.0 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=dusNzVHjfKaiukzRB41yr/s6yq2V49sZ48P4zKeJMi2cyh/hCg26VEJHAQzTs9HR6U jHOtriWe9g7rr7dWzCJx7l9qmJPH18PLzUnHJ8AqzDD+cfx2qUF00zNAA7Zl2TPpiFFJ HXPXqmE6jPZOnTlSkMup9msaoEYRRHhSXjjqHE139o8iU7tuYlAPePpNTwyQgshqrBwH r5RIqYfhcXOa2Q6RSHnjBuecw6gVVpd519WjmdDtaUEt+UOVfqlWcATOEU6SfI44F54E HAseDUp6c0bAPSs5qKzpFBLxKvjAoaaaOWuUYv8rF1ZaQGqLobWE0BGEF93A17g779An zWjA== X-Gm-Message-State: ABy/qLY/Fb/9VQN7SzIguQn6Fd4Vj84AP4ToCa4KY/6gdqzKXfKd+zW+ 9bcegaAnL05HkLNLhmtFep5tvVqofQHbvTi7W8htbdp4ShDjXP/EO+iXGsd2zNizSWXa/eDuvmA lF4fhuf7kybe9GhqZ X-Received: by 2002:a05:6214:762:b0:616:870c:96b8 with SMTP id f2-20020a056214076200b00616870c96b8mr17420020qvz.3.1689837530204; 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) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,PLING_QUERY, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net 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