From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 6D1093A6B67; Sat, 17 Oct 2026 16:13:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792253599; cv=none; b=mo2/iYrhIYQnofFy/a7lvpPwuXi/hfgI7rciq2G6TrrVkLkyGav71AWAYjCjP1XNM473ZSxYxNzb/AbXhTdxGmSExVC2MVEl0kBZY6s3Y/gxf2ZF6Yov/IwWFJKaRag1cLzx4p56iyQ9czIVMkzDlq+XMfy9LZm0+Zy5WDak61U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792253599; c=relaxed/simple; bh=vBZpuwHB3iCBjAUr/X4qiXGH4d0cJRU974PHY5l+Ui0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e1YESfsBoEtuLfJ/mku5ovpS0zctYV+65d/UGkdcb2yxq7XnK9E3A3C6dBEEVdw3llXrERvL3SyLNDsRnHcY04ZyUFdZBl5DRaPO9/0oZ8hn5F0EomgrTMJi2An9NG5CIY1isuouwTvKMryMbdFCa8GcIaZQ4lgoSQvawRy8/vA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GRhWpboO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GRhWpboO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 939A81F000C6; Sat, 17 Oct 2026 16:13:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792253595; bh=T/4XdOZs7B7cIty55hDl5+t3WN36lahBkxMISCz9/Dc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GRhWpboOxKQigAhPuUVhUS7NKuSqT/O6MpVEZFB8c6CI6B6i1GeQJhNTG3nXeLYYo xKnm+KKYY5xweGBUGpvJ/76q04YHk2HrzwJIb9Ov82jAsdsmHz3TdUjuh/2mCm1gjw HZBxYv788VCSUBxwWpyzT4eQ5ZH8TOGiAEItUHwE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Johan Hovold , Chris Lew , Manivannan Sadhasivam , Jeff Hugo , Loic Poulain , Paolo Abeni , Sasha Levin , Jeff Johnson Subject: [PATCH 6.12 171/869] net: qrtr: Drop the MHI auto_queue feature for IPCR DL channels Date: Sat, 17 Oct 2026 17:50:12 +0200 Message-ID: <20261017160041.437924997@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Manivannan Sadhasivam [ Upstream commit 51731792a25cb312ca94cdccfa139eb46de1b2ef ] 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. 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 Reviewed-by: Jeff Hugo Reviewed-by: Loic Poulain Acked-by: Jeff Johnson # drivers/net/wireless/ath/... Acked-by: Jeff Hugo Acked-by: Paolo Abeni Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20251218-qrtr-fix-v2-1-c7499bfcfbe0@oss.qualcomm.com Signed-off-by: Sasha Levin --- drivers/accel/qaic/mhi_controller.c | 24 ---------- drivers/bus/mhi/host/pci_generic.c | 20 +------- drivers/net/wireless/ath/ath11k/mhi.c | 4 -- drivers/net/wireless/ath/ath12k/mhi.c | 4 -- net/qrtr/mhi.c | 69 ++++++++++++++++++++++----- 5 files changed, 60 insertions(+), 61 deletions(-) diff --git a/drivers/accel/qaic/mhi_controller.c b/drivers/accel/qaic/mhi_controller.c index ada9b1eb0787e..8b3a0690ee8fa 100644 --- a/drivers/accel/qaic/mhi_controller.c +++ b/drivers/accel/qaic/mhi_controller.c @@ -34,7 +34,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -50,7 +49,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -66,7 +64,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -82,7 +79,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -98,7 +94,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -114,7 +109,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -130,7 +124,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -146,7 +139,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -162,7 +154,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -178,7 +169,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -194,7 +184,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -210,7 +199,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -226,7 +214,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -242,7 +229,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -258,7 +244,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -274,7 +259,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -290,7 +274,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -306,7 +289,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -322,7 +304,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -338,7 +319,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -354,7 +334,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -370,7 +349,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -386,7 +364,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, { @@ -402,7 +379,6 @@ static const struct mhi_channel_config aic100_channels[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, .wake_capable = false, }, }; diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c index 833d0c940477d..5fc526ddece27 100644 --- a/drivers/bus/mhi/host/pci_generic.c +++ b/drivers/bus/mhi/host/pci_generic.c @@ -86,22 +86,6 @@ struct mhi_pci_dev_info { .doorbell_mode_switch = false, \ } -#define MHI_CHANNEL_CONFIG_DL_AUTOQUEUE(ch_num, ch_name, el_count, ev_ring) \ - { \ - .num = ch_num, \ - .name = ch_name, \ - .num_elements = el_count, \ - .event_ring = ev_ring, \ - .dir = DMA_FROM_DEVICE, \ - .ee_mask = BIT(MHI_EE_AMSS), \ - .pollcfg = 0, \ - .doorbell = MHI_DB_BRST_DISABLE, \ - .lpm_notify = false, \ - .offload_channel = false, \ - .doorbell_mode_switch = false, \ - .auto_queue = true, \ - } - #define MHI_EVENT_CONFIG_CTRL(ev_ring, el_count) \ { \ .num_elements = el_count, \ @@ -253,7 +237,7 @@ static const struct mhi_channel_config modem_qcom_v1_mhi_channels[] = { MHI_CHANNEL_CONFIG_UL(14, "QMI", 4, 0), MHI_CHANNEL_CONFIG_DL(15, "QMI", 4, 0), MHI_CHANNEL_CONFIG_UL(20, "IPCR", 8, 0), - MHI_CHANNEL_CONFIG_DL_AUTOQUEUE(21, "IPCR", 8, 0), + MHI_CHANNEL_CONFIG_DL(21, "IPCR", 8, 0), MHI_CHANNEL_CONFIG_UL_FP(34, "FIREHOSE", 32, 0), MHI_CHANNEL_CONFIG_DL_FP(35, "FIREHOSE", 32, 0), MHI_CHANNEL_CONFIG_UL(46, "IP_SW0", 64, 2), @@ -618,7 +602,7 @@ static const struct mhi_channel_config mhi_telit_fn980_hw_v1_channels[] = { MHI_CHANNEL_CONFIG_UL(14, "QMI", 32, 0), MHI_CHANNEL_CONFIG_DL(15, "QMI", 32, 0), MHI_CHANNEL_CONFIG_UL(20, "IPCR", 16, 0), - MHI_CHANNEL_CONFIG_DL_AUTOQUEUE(21, "IPCR", 16, 0), + MHI_CHANNEL_CONFIG_DL(21, "IPCR", 16, 0), MHI_CHANNEL_CONFIG_HW_UL(100, "IP_HW0", 128, 1), MHI_CHANNEL_CONFIG_HW_DL(101, "IP_HW0", 128, 2), }; diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c index 6974a551883fc..9c2200cc0348b 100644 --- a/drivers/net/wireless/ath/ath11k/mhi.c +++ b/drivers/net/wireless/ath/ath11k/mhi.c @@ -34,7 +34,6 @@ static const struct mhi_channel_config ath11k_mhi_channels_qca6390[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, }, { .num = 21, @@ -48,7 +47,6 @@ static const struct mhi_channel_config ath11k_mhi_channels_qca6390[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = true, }, }; @@ -99,7 +97,6 @@ static const struct mhi_channel_config ath11k_mhi_channels_qcn9074[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, }, { .num = 21, @@ -113,7 +110,6 @@ static const struct mhi_channel_config ath11k_mhi_channels_qcn9074[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = true, }, }; diff --git a/drivers/net/wireless/ath/ath12k/mhi.c b/drivers/net/wireless/ath/ath12k/mhi.c index df96b0f91f54c..af303b9e8acc7 100644 --- a/drivers/net/wireless/ath/ath12k/mhi.c +++ b/drivers/net/wireless/ath/ath12k/mhi.c @@ -31,7 +31,6 @@ static const struct mhi_channel_config ath12k_mhi_channels_qcn9274[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, }, { .num = 21, @@ -45,7 +44,6 @@ static const struct mhi_channel_config ath12k_mhi_channels_qcn9274[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = true, }, }; @@ -96,7 +94,6 @@ static const struct mhi_channel_config ath12k_mhi_channels_wcn7850[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = false, }, { .num = 21, @@ -110,7 +107,6 @@ static const struct mhi_channel_config ath12k_mhi_channels_wcn7850[] = { .lpm_notify = false, .offload_channel = false, .doorbell_mode_switch = false, - .auto_queue = true, }, }; diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c index 69f53625a049d..80e341d2f8a45 100644 --- a/net/qrtr/mhi.c +++ b/net/qrtr/mhi.c @@ -24,13 +24,25 @@ static void qcom_mhi_qrtr_dl_callback(struct mhi_device *mhi_dev, struct qrtr_mhi_dev *qdev = dev_get_drvdata(&mhi_dev->dev); int rc; - if (!qdev || mhi_res->transaction_status) + if (!qdev || (mhi_res->transaction_status && mhi_res->transaction_status != -ENOTCONN)) return; + /* Channel got reset. So just free the buffer */ + if (mhi_res->transaction_status == -ENOTCONN) { + devm_kfree(&mhi_dev->dev, mhi_res->buf_addr); + return; + } + rc = qrtr_endpoint_post(&qdev->ep, mhi_res->buf_addr, mhi_res->bytes_xferd); if (rc == -EINVAL) dev_err(qdev->dev, "invalid ipcrouter packet\n"); + + /* Done with the buffer, now recycle it for future use */ + rc = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, mhi_res->buf_addr, + mhi_dev->mhi_cntrl->buffer_len, MHI_EOT); + if (rc) + dev_err(&mhi_dev->dev, "Failed to recycle the buffer: %d\n", rc); } /* From QRTR to MHI */ @@ -72,6 +84,29 @@ static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb) return rc; } +static int qcom_mhi_qrtr_queue_dl_buffers(struct mhi_device *mhi_dev) +{ + u32 free_desc; + void *buf; + int ret; + + free_desc = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + while (free_desc--) { + buf = devm_kmalloc(&mhi_dev->dev, mhi_dev->mhi_cntrl->buffer_len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, mhi_dev->mhi_cntrl->buffer_len, + MHI_EOT); + if (ret) { + dev_err(&mhi_dev->dev, "Failed to queue buffer: %d\n", ret); + return ret; + } + } + + return 0; +} + static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev, const struct mhi_device_id *id) { @@ -87,20 +122,30 @@ static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev, qdev->ep.xmit = qcom_mhi_qrtr_send; dev_set_drvdata(&mhi_dev->dev, qdev); - rc = qrtr_endpoint_register(&qdev->ep, QRTR_EP_NID_AUTO); - if (rc) - return rc; /* start channels */ - rc = mhi_prepare_for_transfer_autoqueue(mhi_dev); - if (rc) { - qrtr_endpoint_unregister(&qdev->ep); + rc = mhi_prepare_for_transfer(mhi_dev); + if (rc) return rc; - } + + rc = qrtr_endpoint_register(&qdev->ep, QRTR_EP_NID_AUTO); + if (rc) + goto err_unprepare; + + rc = qcom_mhi_qrtr_queue_dl_buffers(mhi_dev); + if (rc) + goto err_unregister; dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n"); return 0; + +err_unregister: + qrtr_endpoint_unregister(&qdev->ep); +err_unprepare: + mhi_unprepare_from_transfer(mhi_dev); + + return rc; } static void qcom_mhi_qrtr_remove(struct mhi_device *mhi_dev) @@ -151,11 +196,13 @@ static int __maybe_unused qcom_mhi_qrtr_pm_resume_early(struct device *dev) if (state == MHI_STATE_M3) return 0; - rc = mhi_prepare_for_transfer_autoqueue(mhi_dev); - if (rc) + rc = mhi_prepare_for_transfer(mhi_dev); + if (rc) { dev_err(dev, "failed to prepare for autoqueue transfer %d\n", rc); + return rc; + } - return rc; + return qcom_mhi_qrtr_queue_dl_buffers(mhi_dev); } static const struct dev_pm_ops qcom_mhi_qrtr_pm_ops = { -- 2.53.0