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 2EC307A for ; Sat, 9 Jul 2022 06:09:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E04EC3411C; Sat, 9 Jul 2022 06:09:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657346949; bh=A0VrllQFD/OTuASUh884+Oug040m4y5tVS+QhLk4yuw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mCRwV1ubPYHVGUQbwNXFhYtjLWwJ66M+lBUhVKUXGpiVAVVB+xTsYfzqc5v/JwKe8 H5S1z/d+jHvn4gWkBXmUUQpHxLImInNsGhzfYEsdZBzYCIlwvObcIpRr4K/vxiqvnY dfas9gBLJ4tdi8WRyUDCBPwArElIvJi5BKD/sjZQcSwmWcSwEahGkv/1aGn6N9y1U9 BRunYmoowxxJaKuM9OLPsOuJAkjeK2Ur0N48Dg06+kQHNv0prjK7wA1HW3r/GMPfeX JkVKH79xuHEvNllaVqXudbztp85sEwYkEcLQ9DHLbzITxuhIAODO4OoiUFG2XYZXZP QDnLOTSpE5uEw== Date: Sat, 9 Jul 2022 11:38:57 +0530 From: Manivannan Sadhasivam To: Maxim Kochetkov Cc: mhi@lists.linux.dev, manivannan.sadhasivam@linaro.org, quic_hemantk@quicinc.com, bbhatt@codeaurora.org, Maxim Kochetkov Subject: Re: [PATCH] net: qrtr: start MHI channel after endpoit creation Message-ID: <20220709060857.GC5063@thinkpad> References: <20220430103430.37349-1-fido_max@inbox.ru> Precedence: bulk X-Mailing-List: mhi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220430103430.37349-1-fido_max@inbox.ru> On Sat, Apr 30, 2022 at 01:34:30PM +0300, Maxim Kochetkov wrote: > From: Maxim Kochetkov > > 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: Manivannan Sadhasivam Thanks, Mani > --- > 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; > + > dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n"); > > return 0; > -- > 2.34.1 > -- மணிவண்ணன் சதாசிவம்