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 C3D15C19F2A for ; Thu, 11 Aug 2022 09:37:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234678AbiHKJhi (ORCPT ); Thu, 11 Aug 2022 05:37:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232585AbiHKJhi (ORCPT ); Thu, 11 Aug 2022 05:37:38 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D39EE90802; Thu, 11 Aug 2022 02:37:36 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 54E61CE1FCB; Thu, 11 Aug 2022 09:37:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF321C433D6; Thu, 11 Aug 2022 09:37:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660210648; bh=hE/Qb0FD4bADTX3ai6AJnDvlPB0Rt0EGI8kSmltGj/E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SDJpHh0nYgdvSobJ3dsR6WHj0c5Yam+qZVVKWF+rwbYrSyDTLmw275TTQE++XM3hC SX1oSZQNdb3VkXpDwgF0S4m1z2EfePKP8ThZksG/NrcWdkCFUAB2tgjXskuXk+BEaG 2hsVrdJiJsHbBbQyrhUlOkhj1cIlMqQi3/T0my26TNx9JJExIYQ+s91jXVLNwAtKNV nXTUeubw/yPv4L0+ahvm1nMhT1jue9/LEEEm3LF570+KjvbYSbAPeeIleqEjs8hQ4y ISop5SP8APX6BJ+IN4ImCIYLYFUTYF+zr32EiVlEtNnrFschuaeHh0/3f8Cf87QqdU 2yJAT+tbrtjUg== Date: Thu, 11 Aug 2022 15:07:21 +0530 From: Manivannan Sadhasivam To: Maxim Kochetkov Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, linux-arm-msm@vger.kernel.org, Hemant Kumar Subject: Re: [PATCH 1/1] net: qrtr: start MHI channel after endpoit creation Message-ID: <20220811093721.GA29799@workstation> References: <20220811092145.1648008-1-fido_max@inbox.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220811092145.1648008-1-fido_max@inbox.ru> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Thu, Aug 11, 2022 at 12:21:45PM +0300, Maxim Kochetkov wrote: > MHI channel may generates event/interrupt right after enabling. > It may leads to 2 race conditions issues. > > 1) > Such event may be dropped by qcom_mhi_qrtr_dl_callback() at check: > > if (!qdev || mhi_res->transaction_status) > return; > > Because dev_set_drvdata(&mhi_dev->dev, qdev) may be not performed at > this moment. In this situation qrtr-ns will be unable to enumerate > services in device. > --------------------------------------------------------------- > > 2) > Such event may come at the moment after dev_set_drvdata() and > before qrtr_endpoint_register(). In this case kernel will panic with > accessing wrong pointer at qcom_mhi_qrtr_dl_callback(): > > rc = qrtr_endpoint_post(&qdev->ep, mhi_res->buf_addr, > mhi_res->bytes_xferd); > > Because endpoint is not created yet. > -------------------------------------------------------------- > So move mhi_prepare_for_transfer_autoqueue after endpoint creation > to fix it. > > Fixes: a2e2cc0dbb11 ("net: qrtr: Start MHI channels during init") > Signed-off-by: Maxim Kochetkov > Reviewed-by: Hemant Kumar > Reviewed-by: Manivannan Sadhasivam > --- > net/qrtr/mhi.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c > index 18196e1c8c2f..17520d9e7a51 100644 > --- a/net/qrtr/mhi.c > +++ b/net/qrtr/mhi.c > @@ -78,11 +78,6 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev, > struct qrtr_mhi_dev *qdev; > int rc; > > - /* start channels */ > - rc = mhi_prepare_for_transfer_autoqueue(mhi_dev); > - if (rc) > - return rc; > - > qdev = devm_kzalloc(&mhi_dev->dev, sizeof(*qdev), GFP_KERNEL); > if (!qdev) > return -ENOMEM; > @@ -96,6 +91,11 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev, > if (rc) > return rc; > > + /* start channels */ > + rc = mhi_prepare_for_transfer_autoqueue(mhi_dev); > + if (rc) > + return rc; I missed the fact that you need to call qrtr_endpoint_unregister() in the error path. Please fix it. Thanks, Mani > + > dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n"); > > return 0; > -- > 2.34.1 >