Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Sat, 1 Jul 2023 21:38:06 +0200
From:   Simon Horman <simon.horman@corigine.com>
To:     Vladimir Oltean <vladimir.oltean@nxp.com>
Cc:     netdev@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: dsa: tag_sja1105: fix source port decoding in
 vlan_filtering=0 bridge mode
Message-ID: <ZKCAngK+ngGrrG3q@corigine.com>
References: <20230630222010.1691671-1-vladimir.oltean@nxp.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230630222010.1691671-1-vladimir.oltean@nxp.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?MB3W1hlrcJVZyTuId1sWbK46dgSU6CPy1i1mNqCy57AobItQzLJeBOUiwPPU?=
 =?us-ascii?Q?WQOk42iAo41uw7jerpGDKQLZrg+CN8mR/PjlMonEZjooFmfvMtG1DMBD9sVD?=
 =?us-ascii?Q?ctWKClWXJ7lQfodqa8Bpe7msxqYfG9FV6CBKasZsxHYdfvVAaQVCE/qqI/gK?=
 =?us-ascii?Q?7DqFiXVbhIu6Mbcoc42TlmJKNxi0swMZ0TATe5BVtkVtxLEhwHVuoo2WVEwc?=
 =?us-ascii?Q?ymS012XaTIwMYLp/qwx2qKxgUQDMRDMLTRTPMvnWc4zKbJAzWr82hIgME6nt?=
 =?us-ascii?Q?YMqlpxxkP0GCRBqaHKflRDsgOWkFHbazc3wVis9ls/t9afMYYAntiR/0eVXi?=
 =?us-ascii?Q?YambRBfH8TS8r0S/InJ0b/6GEJ6xx//gtHqyzg+6Qw0Az+vUWd/+J/wq/Mut?=
 =?us-ascii?Q?aXkgdqb8v0Ol695dYhNiLGP21JE8KiT2IdKYaFftNnjcXkZOCrKakpjhWzep?=
 =?us-ascii?Q?21fjPRUCo58wtGrgRDcg5TD9NkX++Ry+1LxZ51pJgP77NzX/Ecb3KnjbpG4e?=
 =?us-ascii?Q?Htofsd/mqjgMo0/MRLbEpcEFKOuSQDxWWx4esE05PcrwFdeZcdeDqYccE1yH?=
 =?us-ascii?Q?kEEUVDgxFXnYjjhXERWc9f+Yer+9BVFe3JTP4V+1xf4wPCK2WO2VRd3NHLwU?=
 =?us-ascii?Q?0kyu4uR8eY+/9byjjs5VdDcBgWM+p6AJZMrOy5sHDA1LujawQzQws9cYGCfH?=
 =?us-ascii?Q?9W25n+SY2k2HrH1mLJgpyq+pDA2//yrPlswSjYnfjFEFKy6hIO3w3UOD0fDB?=
 =?us-ascii?Q?4IgylcZPzSEwdDCJVMxykRrORux5DJDuvrbCcDQlh/2wfa4+CwDvL0bc52mm?=
 =?us-ascii?Q?gHnn7IwMGeU6OnafYeVU/VeMUjgGyE5gx9S1Dvbp4GyhBlEfk2zjx0WcNusw?=
 =?us-ascii?Q?kLoz7y2D0CJg0tH7NHzFuHe8EyRWKIolQNHn4IQoEidT5Nm+eNNlciAgCcQu?=
 =?us-ascii?Q?DNUFOsIZk+Pmp/KYdew02C8toqxJaHqjArzcgvIlgkBt3n3iFrzQnfLjUkGs?=
 =?us-ascii?Q?96kteqp5xiZ27FLfR69yRQ9a5vy+8VEV58Xwdbf1qc1+EVQ+5lTXH6tGbaOI?=
 =?us-ascii?Q?lbb6CnuZEHi94SRvrUwpHkIpynJxiFYgljV4VghHxpSv60Z53E9PzHPD4Zcp?=
 =?us-ascii?Q?iJSIP03lp2NCJWYrMb35t4N/0eKjZcK930saUjDPl2r2G8M9nRvv9MAdobEz?=
 =?us-ascii?Q?E608nIVfitsl93rTKY1t0uWrNZSOQunY6CxMdEmCWVZrLUqVHb0l/taPTx57?=
 =?us-ascii?Q?Rxm7HKbjv3wqsd0bFMvwZxoTY+zd8PLfOc6LLhbGWQEncoS6eBenIVx4qstE?=
 =?us-ascii?Q?Hx2UfzcrWta+Yj3OJEPGekTCGVasUxRdj+YWpg+v2x7JvCaVQf9DOoNovi88?=
 =?us-ascii?Q?NADVqjqbbMB97lb6ynRLPHGbEqVY4eTq0jkl444JBTUaDRXRUmm+u9LH9BKA?=
 =?us-ascii?Q?x0/NKuf1pqacLNfdIOwfr8xzxk0P2b37H3dhaWet22wJsLh0JPMJeZVqeUma?=
 =?us-ascii?Q?lF120A1OBXnI5/r4jTJZxF2tYX0yS/3LOs5zD4Y/jfPpL6AOUYuSFIlOEjVx?=
 =?us-ascii?Q?yT4YoYbFv/+CweWF92EirAJJPNxgd4k7pzEiO+GupxFuqwd6MQK/v9uXcrqj?=
 =?us-ascii?Q?Bg=3D=3D?=
X-OriginatorOrg: corigine.com
X-MS-Exchange-CrossTenant-Network-Message-Id: a875202f-5301-41bb-e65a-08db7a6ab99b
X-MS-Exchange-CrossTenant-AuthSource: PH0PR13MB4842.namprd13.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Jul 2023 19:38:20.4071
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: fe128f2c-073b-4c20-818e-7246a585940c
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: VfQp+bljRIhrBBmRNcTiCcMXMVfV47NRuSYjVfNfU7BtUuIcCtihJjh/9OAtCBnCaX1986EBZWzv/Rj5nFlroomW+MdkwGrec6Icw5kFzqk=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR13MB6122
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,
        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
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, Jul 01, 2023 at 01:20:10AM +0300, Vladimir Oltean wrote:
> There was a regression introduced by the blamed commit, where pinging to
> a VLAN-unaware bridge would fail with the repeated message "Couldn't
> decode source port" coming from the tagging protocol driver.
> 
> When receiving packets with a bridge_vid as determined by
> dsa_tag_8021q_bridge_join(), dsa_8021q_rcv() will decode:
> - source_port = 0 (which isn't really valid, more like "don't know")
> - switch_id = 0 (which isn't really valid, more like "don't know")
> - vbid = value in range 1-7
> 
> Since the blamed patch has reversed the order of the checks, we are now
> going to believe that source_port != -1 and switch_id != -1, so they're
> valid, but they aren't.
> 
> The minimal solution to the problem is to only populate source_port and
> switch_id with what dsa_8021q_rcv() came up with, if the vbid is zero,
> i.e. the source port information is trustworthy.
> 
> Fixes: c1ae02d87689 ("net: dsa: tag_sja1105: always prefer source port information from INCL_SRCPT")
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Simon Horman <simon.horman@corigine.com>