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[199.106.103.254]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12061a93616sm517453c88.14.2025.12.17.10.18.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Dec 2025 10:18:36 -0800 (PST) Message-ID: <5e568034-20a3-4ed5-a8e0-c010e5aa7b82@oss.qualcomm.com> Date: Wed, 17 Dec 2025 10:18:34 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] net: qrtr: Drop the MHI auto_queue feature for IPCR DL channels To: manivannan.sadhasivam@oss.qualcomm.com, Jeff Hugo , Carl Vanderlip , Oded Gabbay , Manivannan Sadhasivam , Jeff Johnson , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Greg Kroah-Hartman , Loic Poulain , Maxim Kochetkov Cc: linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, mhi@lists.linux.dev, linux-wireless@vger.kernel.org, ath11k@lists.infradead.org, ath12k@lists.infradead.org, netdev@vger.kernel.org, Bjorn Andersson , Johan Hovold , Chris Lew , stable@vger.kernel.org References: <20251217-qrtr-fix-v1-0-f6142a3ec9d8@oss.qualcomm.com> <20251217-qrtr-fix-v1-1-f6142a3ec9d8@oss.qualcomm.com> From: Jeff Johnson Content-Language: en-US In-Reply-To: <20251217-qrtr-fix-v1-1-f6142a3ec9d8@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMjE3MDE0NSBTYWx0ZWRfX/plA96zhZhY8 VvbXdhMpB40OLBiETj5siz0sFW/V2me887PTRhPwlfFwHpn+LbfNARwzI95mwdTm3AkKJGKcr7X 6CAPRYh+0Sezlg5gEWxA3rtFzRejKLkPUr6j+S5haAwsFkZXhB2BRfJ0+dy7JJPKi9biG+gAraQ VD59UJsR99Lg34RaCmc8SWNMZmeo9OJuN8XPGzXYnoO1+Du2kaFNKmnIrA8UJzPRjqC1G427egB 3iCBlXYwREkVIKXsAlKZVhQpT8keb/p70pQhqAaiUVKR7k61HfYBeHEa7BbNO0/AzeTsziFI58Y 4ijUvjG+Cc/fOTqamWphSjfWN+gU4QnC5vAIjJOX6nMLqBa0qUOxI/0CRABRlJ93tC2l7IMpBsk hUa3MDNj1g2ccCexn0OZN9cNxrtDlw== X-Proofpoint-GUID: 9rfAolldRzDRLWN_9lBhVAfinu-Ckhn3 X-Proofpoint-ORIG-GUID: 9rfAolldRzDRLWN_9lBhVAfinu-Ckhn3 X-Authority-Analysis: v=2.4 cv=EsHfbCcA c=1 sm=1 tr=0 ts=6942f3fd cx=c_pps a=Qgeoaf8Lrialg5Z894R3/Q==:117 a=JYp8KDb2vCoCEuGobkYCKw==:17 a=IkcTkHD0fZMA:10 a=wP3pNCr1ah4A:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=zitRP-D0AAAA:8 a=EUspDBNiAAAA:8 a=COk6AnOGAAAA:8 a=isMaZ9OHK7bkWVW8W2QA:9 a=QEXdDO2ut3YA:10 a=x9snwWr2DeNwDh03kgHS:22 a=xwnAI6pc5liRhupp6brZ:22 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-12-17_03,2025-12-16_05,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 bulkscore=0 priorityscore=1501 suspectscore=0 impostorscore=0 clxscore=1015 lowpriorityscore=0 phishscore=0 spamscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2510240001 definitions=main-2512170145 On 12/17/2025 9:16 AM, Manivannan Sadhasivam via B4 Relay wrote: > From: Manivannan Sadhasivam > > MHI stack offers the 'auto_queue' feature, which allows the MHI stack to > auto queue the buffers for the RX path (DL channel). Though this feature > simplifies the client driver design, it introduces race between the client > drivers and the MHI stack. For instance, with auto_queue, the 'dl_callback' > for the DL channel may get called before the client driver is fully probed. > This means, by the time the dl_callback gets called, the client driver's > structures might not be initialized, leading to NULL ptr dereference. > > Currently, the drivers have to workaround this issue by initializing the > internal structures before calling mhi_prepare_for_transfer_autoqueue(). > But even so, there is a chance that the client driver's internal code path > may call the MHI queue APIs before mhi_prepare_for_transfer_autoqueue() is > called, leading to similar NULL ptr dereference. This issue has been > reported on the Qcom X1E80100 CRD machines affecting boot. > > So to properly fix all these races, drop the MHI 'auto_queue' feature > altogether and let the client driver (QRTR) manage the RX buffers manually. > In the QRTR driver, queue the RX buffers based on the ring length during > probe and recycle the buffers in 'dl_callback' once they are consumed. This > also warrants removing the setting of 'auto_queue' flag from controller > drivers. > > Currently, this 'auto_queue' feature is only enabled for IPCR DL channel. > So only the QRTR client driver requires the modification. > > Cc: stable@vger.kernel.org > Fixes: 227fee5fc99e ("bus: mhi: core: Add an API for auto queueing buffers for DL channel") > Fixes: 68a838b84eff ("net: qrtr: start MHI channel after endpoit creation") > Reported-by: Johan Hovold > Closes: https://lore.kernel.org/linux-arm-msm/ZyTtVdkCCES0lkl4@hovoldconsulting.com > Suggested-by: Chris Lew > Signed-off-by: Manivannan Sadhasivam Acked-by: Jeff Johnson # drivers/net/wireless/ath/...