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 7821DC25B0F for ; Sat, 13 Aug 2022 00:09:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233705AbiHMAJa (ORCPT ); Fri, 12 Aug 2022 20:09:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229719AbiHMAJ3 (ORCPT ); Fri, 12 Aug 2022 20:09:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C8085C9EB; Fri, 12 Aug 2022 17:09:28 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 06D4C61753; Sat, 13 Aug 2022 00:09:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02A62C433C1; Sat, 13 Aug 2022 00:09:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660349367; bh=5yIuU8S7Bxx4QtQzdZvHC4r+a75zJUOpa3eix4D1VOY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=F3nnxdAZZjxa0g1rP6pr9Rf9UgOIjK5jMf6wmRKk0w7VZNdl3oN9w1z7picsDUV5C pxkNajE8hTmdTv+ljdXIKyXe0b0rXTh3IuD/RQnocBcdL0PMib2o1tdxgDRulSfSE4 jO2IG1P2IdnxRXh/vdR4kQsDsc7rJg8lEQLIiSdRdeYt3HNXMjbRWYj3Y6IzB1DHlB NEIpxIDZuXCGp/Hcxuu1KM69KYLO/jIHqCTD2tVoQct6Vvkva97n46Os7Wj4aFWteD bopfRVCIbb3ehgEXFK0JZcUf8ggtufd2h7aTh5zHsoWZhaF9xaxwjpVG0Fsv91jx+Q Yx5Ay6aw+WdYQ== Date: Fri, 12 Aug 2022 17:09:26 -0700 From: Jakub Kicinski To: Maxim Kochetkov , loic.poulain@linaro.org Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, linux-arm-msm@vger.kernel.org, Hemant Kumar , Manivannan Sadhasivam Subject: Re: [PATCH v2 1/1] net: qrtr: start MHI channel after endpoit creation Message-ID: <20220812170926.0370b05d@kernel.org> In-Reply-To: <20220811094840.1654088-1-fido_max@inbox.ru> References: <20220811094840.1654088-1-fido_max@inbox.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 11 Aug 2022 12:48:40 +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 You must CC the author of the patch under Fixes, they are usually the best person to review the fix. Adding Loic now. > diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c > index 18196e1c8c2f..9ced13c0627a 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 +91,13 @@ 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) { > + qrtr_endpoint_unregister(&qdev->ep); > + return rc; > + } > + > dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n"); > > return 0;