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 D9929C433F5 for ; Wed, 23 Mar 2022 11:43:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243965AbiCWLol (ORCPT ); Wed, 23 Mar 2022 07:44:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243973AbiCWLoi (ORCPT ); Wed, 23 Mar 2022 07:44:38 -0400 Received: from mail-lj1-x230.google.com (mail-lj1-x230.google.com [IPv6:2a00:1450:4864:20::230]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79895E093; Wed, 23 Mar 2022 04:43:08 -0700 (PDT) Received: by mail-lj1-x230.google.com with SMTP id 17so1447702lji.1; Wed, 23 Mar 2022 04:43:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:in-reply-to:references:date:message-id :mime-version; bh=GUNacRM0Kzot4Ci3+9/rQiAP6HGdFO8cNfIKSh2/JpE=; b=Jdm0puZZ/Q6dFz353KCoDZvifEBG6tzHxW6igmTgxd+obwpPQAudDXwNknS/hhz/dn qCVif8Hnrp91CoRN93+vhhSXQr3O0aViX2rpkgbxco2CgKXm4vcj3xV/rB7waIx9ztsB R0mmMVc818zGQV6acVGBsI2XRGtQi23j0NZdJQ3tP5uOe3ghbIsHipM4baigfeZK+Sfz 9sAsxvFUgiFl3NTSys9UjwoH0U+wR2PDNR7Z1KBKZCVkk4oU810jgtSTRDxyYTPoLCQd Dlvwu7iShS+Uf6N70yehFjkjjuL8gZFZjRNybtYbtHRcPvurxM4JhK/VMh4Hvuhcn2/e dgZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=GUNacRM0Kzot4Ci3+9/rQiAP6HGdFO8cNfIKSh2/JpE=; b=YBptG7s4kYIWcYn12GFL85yxSDWaaElDrVkuOh2sSrNU/CXA5YbS0gSZ7MfWlhctt8 +FDGUfXATUZie9cSg211+vWBlBhd9pydc4hpFodKShlTT7+Z48o6BO7cx2wH0XnNi/V/ KyRFPauHvlRnPtzP9tAAuCYoChHBLGscdZ2MvNHn0d0PqOATM7t/EINCDaubYAxndv23 ypaE3hhUYVDBzXA/az35LagtVmB/ydYQSoIiIX5neeYelRcKRPZbFcsDmi8DbvTJCeT/ D8f9w3jNAbp0wj5Skcg9GjKpV3FFjG7MWJLuL6UNCFsA0eTt1FkWdGm4z8qjBSEJmGdY Nijw== X-Gm-Message-State: AOAM53395V6mVJIq7HKSE6Ri5Q7CkmAPXr7pGk7sBnqB4z7Ol2pTBLvi e3NeS/gSFUtMsrZ+IWLgTUpvblpdLu4vuw== X-Google-Smtp-Source: ABdhPJykafU9a03wA5avbF9HT0x528x5zTqhH1AL31w9rXO/uO4pFDwD6bruH4dLIxrv5tOUpAMGvQ== X-Received: by 2002:a2e:7d18:0:b0:247:f205:96fa with SMTP id y24-20020a2e7d18000000b00247f20596famr23072028ljc.269.1648035786533; Wed, 23 Mar 2022 04:43:06 -0700 (PDT) Received: from wse-c0127 ([208.127.141.29]) by smtp.gmail.com with ESMTPSA id k2-20020a056512330200b0044a096ea7absm2008256lfe.54.2022.03.23.04.43.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Mar 2022 04:43:06 -0700 (PDT) From: Hans Schultz X-Google-Original-From: Hans Schultz To: Vladimir Oltean , Hans Schultz Cc: Andrew Lunn , davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, Vivien Didelot , Florian Fainelli , Jiri Pirko , Ivan Vecera , Roopa Prabhu , Nikolay Aleksandrov , Daniel Borkmann , Ido Schimmel , linux-kernel@vger.kernel.org, bridge@lists.linux-foundation.org Subject: Re: [PATCH net-next 3/3] net: dsa: mv88e6xxx: mac-auth/MAB implementation In-Reply-To: <20220323112116.q6shx2g4r23ungtc@skbuf> References: <20220317172013.rhjvknre5w7mfmlo@skbuf> <86tubvk24r.fsf@gmail.com> <20220318121400.sdc4guu5m4auwoej@skbuf> <86pmmjieyl.fsf@gmail.com> <20220318131943.hc7z52beztqlzwfq@skbuf> <86a6dixnd2.fsf@gmail.com> <20220322110806.kbdb362jf6pbtqaf@skbuf> <86fsn90ye8.fsf@gmail.com> <20220323101643.kum3nuqctunakcfo@skbuf> <864k3p5437.fsf@gmail.com> <20220323112116.q6shx2g4r23ungtc@skbuf> Date: Wed, 23 Mar 2022 12:43:03 +0100 Message-ID: <86tuboao8o.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On ons, mar 23, 2022 at 13:21, Vladimir Oltean wrote: > On Wed, Mar 23, 2022 at 11:57:16AM +0100, Hans Schultz wrote: >> >> >> Another issue I see, is that there is a deadlock or similar issue when >> >> >> receiving violations and running 'bridge fdb show' (it seemed that >> >> >> member violations also caused this, but not sure yet...), as the unit >> >> >> freezes, not to return... >> >> > >> >> > Have you enabled lockdep, debug atomic sleep, detect hung tasks, things >> >> > like that? >> >> >> >> I have now determined that it is the rtnl_lock() that causes the >> >> "deadlock". The doit() in rtnetlink.c is under rtnl_lock() and is what >> >> takes care of getting the fdb entries when running 'bridge fdb show'. In >> >> principle there should be no problem with this, but I don't know if some >> >> interrupt queue is getting jammed as they are blocked from rtnetlink.c? >> > >> > Sorry, I forgot to respond yesterday to this. >> > By any chance do you maybe have an AB/BA lock inversion, where from the >> > ATU interrupt handler you do mv88e6xxx_reg_lock() -> rtnl_lock(), while >> > from the port_fdb_dump() handler you do rtnl_lock() -> mv88e6xxx_reg_lock()? >> >> If I release the mv88e6xxx_reg_lock() before calling the handler, I need >> to get it again for the mv88e6xxx_g1_atu_loadpurge() call at least. But >> maybe the vtu_walk also needs the mv88e6xxx_reg_lock()? >> I could also just release the mv88e6xxx_reg_lock() before the >> call_switchdev_notifiers() call and reacquire it immediately after? > > The cleanest way to go about this would be to have the call_switchdev_notifiers() > portion of the ATU interrupt handling at the very end of mv88e6xxx_g1_atu_prob_irq_thread_fn(), > with no hardware access needed, and therefore no reg_lock() held. So something like? mv88e6xxx_reg_unlock(chip); rtnl_lock(); err = call_switchdev_notifiers(SWITCHDEV_FDB_ADD_TO_BRIDGE, brport, &info.info, NULL); rtnl_unlock(); mv88e6xxx_reg_lock(chip);