From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7F52514AB6 for ; Thu, 3 Aug 2023 19:29:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98713C433C7; Thu, 3 Aug 2023 19:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1691090986; bh=SzD6mLWXBeRO+za53POXhdBCgv8KiAzF/i4NjDRIS8k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=N0i+JQtBNRBqg3BZOsF012kHvX6aeQoV7b5HpqRsPTW8rqYNjmweL+fpQ/3wGLxAN aZ7j7i0Zcah44YMxFHZCTL8peJL1nLbv0du0/DE/iNwrtRMtGS7nStLQfGfpV6Tl5N gEkUfIOuZziEO01aUc+4LQtLFsY6TfJ+FjdW4ih2hFOe7gXmouosSkOC+dUVHE0SXQ ERWlYXOsDd5dX8jVwdBXBTIeU0bL7DDe5tpGeeS1ctUPdOfzei7FUSSaXoKselhJn/ hyJzkxhlJkhaluBldQ7F181vMR5AK87LmcVGCxNE23WNeTdYi/EqBcoNG6+wKmYRzZ 4MRsMCq52/K4A== Date: Thu, 3 Aug 2023 21:29:38 +0200 From: Simon Horman To: Vladimir Oltean Cc: netdev@vger.kernel.org, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Andrew Lunn , Florian Fainelli , Claudiu Manoil , Alexandre Belloni , UNGLinuxDriver@microchip.com, Colin Foster Subject: Re: [PATCH net] net: dsa: ocelot: call dsa_tag_8021q_unregister() under rtnl_lock() on driver remove Message-ID: References: <20230803134253.2711124-1-vladimir.oltean@nxp.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230803134253.2711124-1-vladimir.oltean@nxp.com> On Thu, Aug 03, 2023 at 04:42:53PM +0300, Vladimir Oltean wrote: > When the tagging protocol in current use is "ocelot-8021q" and we unbind > the driver, we see this splat: > > $ echo '0000:00:00.2' > /sys/bus/pci/drivers/fsl_enetc/unbind > mscc_felix 0000:00:00.5 swp0: left promiscuous mode > sja1105 spi2.0: Link is Down > DSA: tree 1 torn down > mscc_felix 0000:00:00.5 swp2: left promiscuous mode > sja1105 spi2.2: Link is Down > DSA: tree 3 torn down > fsl_enetc 0000:00:00.2 eno2: left promiscuous mode > mscc_felix 0000:00:00.5: Link is Down > ------------[ cut here ]------------ > RTNL: assertion failed at net/dsa/tag_8021q.c (409) > WARNING: CPU: 1 PID: 329 at net/dsa/tag_8021q.c:409 dsa_tag_8021q_unregister+0x12c/0x1a0 > Modules linked in: > CPU: 1 PID: 329 Comm: bash Not tainted 6.5.0-rc3+ #771 > pc : dsa_tag_8021q_unregister+0x12c/0x1a0 > lr : dsa_tag_8021q_unregister+0x12c/0x1a0 > Call trace: > dsa_tag_8021q_unregister+0x12c/0x1a0 > felix_tag_8021q_teardown+0x130/0x150 > felix_teardown+0x3c/0xd8 > dsa_tree_teardown_switches+0xbc/0xe0 > dsa_unregister_switch+0x168/0x260 > felix_pci_remove+0x30/0x60 > pci_device_remove+0x4c/0x100 > device_release_driver_internal+0x188/0x288 > device_links_unbind_consumers+0xfc/0x138 > device_release_driver_internal+0xe0/0x288 > device_driver_detach+0x24/0x38 > unbind_store+0xd8/0x108 > drv_attr_store+0x30/0x50 > ---[ end trace 0000000000000000 ]--- > ------------[ cut here ]------------ > RTNL: assertion failed at net/8021q/vlan_core.c (376) > WARNING: CPU: 1 PID: 329 at net/8021q/vlan_core.c:376 vlan_vid_del+0x1b8/0x1f0 > CPU: 1 PID: 329 Comm: bash Tainted: G W 6.5.0-rc3+ #771 > pc : vlan_vid_del+0x1b8/0x1f0 > lr : vlan_vid_del+0x1b8/0x1f0 > dsa_tag_8021q_unregister+0x8c/0x1a0 > felix_tag_8021q_teardown+0x130/0x150 > felix_teardown+0x3c/0xd8 > dsa_tree_teardown_switches+0xbc/0xe0 > dsa_unregister_switch+0x168/0x260 > felix_pci_remove+0x30/0x60 > pci_device_remove+0x4c/0x100 > device_release_driver_internal+0x188/0x288 > device_links_unbind_consumers+0xfc/0x138 > device_release_driver_internal+0xe0/0x288 > device_driver_detach+0x24/0x38 > unbind_store+0xd8/0x108 > drv_attr_store+0x30/0x50 > DSA: tree 0 torn down > > This was somewhat not so easy to spot, because "ocelot-8021q" is not the > default tagging protocol, and thus, not everyone who tests the unbinding > path may have switched to it beforehand. The default > felix_tag_npi_teardown() does not require rtnl_lock() to be held. > > Fixes: 7c83a7c539ab ("net: dsa: add a second tagger for Ocelot switches based on tag_8021q") > Signed-off-by: Vladimir Oltean > --- > drivers/net/dsa/ocelot/felix.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c > index fd7eb4a52918..9a3e5ec16972 100644 > --- a/drivers/net/dsa/ocelot/felix.c > +++ b/drivers/net/dsa/ocelot/felix.c > @@ -1619,8 +1619,10 @@ static void felix_teardown(struct dsa_switch *ds) > struct felix *felix = ocelot_to_felix(ocelot); > struct dsa_port *dp; > > + rtnl_lock(); > if (felix->tag_proto_ops) > felix->tag_proto_ops->teardown(ds); > + rtnl_unlock(); Hi Vladimir, I am curious to know if RTNL could be taken in felix_tag_8021q_teardown() instead. > > dsa_switch_for_each_available_port(dp, ds) > ocelot_deinit_port(ocelot, dp->index); > -- > 2.34.1 > >