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 0F30019891 for ; Fri, 4 Aug 2023 20:53:18 +0000 (UTC) Received: from out-103.mta0.migadu.com (out-103.mta0.migadu.com [91.218.175.103]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 810BD4EC4 for ; Fri, 4 Aug 2023 13:53:15 -0700 (PDT) Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1691182393; 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=ZL/Zfz+ulrtV+p+UIKOwsglDo56pQvjadHQdqAJUcn0=; b=JPUQAgcQ0PZJ+XFAl0EtbUGUO45TktXdQyDbd71Wm9uLPy0joN4Q1FX4HC/qy4c2Gkd4wH I5XoWHzy0TgZBCuUvDeUy6zqUfuMQbjNEET++ijXqOisg3T3D+MNCAmbq7kRhYVtzHgW9F OrjU9WYF3ECgdZZF7wu8+ja/QoPCUH4= Date: Fri, 4 Aug 2023 21:53:12 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH net-next] net/mlx5: Devcom, only use devcom after NULL check in mlx5_devcom_send_event() Content-Language: en-US To: Li Zetao , saeedm@nvidia.com, leon@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org Cc: pabeni@redhat.com, shayd@nvidia.com, roid@nvidia.com, mbloch@nvidia.com, vladbu@nvidia.com, elic@nvidia.com, netdev@vger.kernel.org, linux-rdma@vger.kernel.org References: <20230804092636.91357-1-lizetao1@huawei.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Vadim Fedorenko In-Reply-To: <20230804092636.91357-1-lizetao1@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 04/08/2023 10:26, Li Zetao wrote: > There is a warning reported by kernel test robot: > > smatch warnings: > drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c:264 > mlx5_devcom_send_event() warn: variable dereferenced before > IS_ERR check devcom (see line 259) > > The reason for the warning is that the pointer is used before check, put > the assignment to comp after devcom check to silence the warning. > > Fixes: 88d162b47981 ("net/mlx5: Devcom, Infrastructure changes") > Reported-by: kernel test robot > Reported-by: Dan Carpenter > Closes: https://lore.kernel.org/r/202308041028.AkXYDwJ6-lkp@intel.com/ > Signed-off-by: Li Zetao > --- > drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c > index feb62d952643..2bc18274858c 100644 > --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c > +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c > @@ -256,7 +256,7 @@ int mlx5_devcom_send_event(struct mlx5_devcom_comp_dev *devcom, > int event, int rollback_event, > void *event_data) > { > - struct mlx5_devcom_comp *comp = devcom->comp; > + struct mlx5_devcom_comp *comp; > struct mlx5_devcom_comp_dev *pos; The code should end up with reverse x-mas tree order. The change itself LGTM. > int err = 0; > void *data; > @@ -264,6 +264,7 @@ int mlx5_devcom_send_event(struct mlx5_devcom_comp_dev *devcom, > if (IS_ERR_OR_NULL(devcom)) > return -ENODEV; > > + comp = devcom->comp; > down_write(&comp->sem); > list_for_each_entry(pos, &comp->comp_dev_list_head, list) { > data = rcu_dereference_protected(pos->data, lockdep_is_held(&comp->sem));