From patchwork Thu Sep 10 12:44:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mansur Alisha Shaik X-Patchwork-Id: 11767769 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3A556698 for ; Thu, 10 Sep 2020 12:45:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 243F52078B for ; Thu, 10 Sep 2020 12:45:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730777AbgIJMpm (ORCPT ); Thu, 10 Sep 2020 08:45:42 -0400 Received: from alexa-out.qualcomm.com ([129.46.98.28]:45909 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730474AbgIJMo7 (ORCPT ); Thu, 10 Sep 2020 08:44:59 -0400 Received: from ironmsg09-lv.qualcomm.com ([10.47.202.153]) by alexa-out.qualcomm.com with ESMTP; 10 Sep 2020 05:44:35 -0700 Received: from ironmsg02-blr.qualcomm.com ([10.86.208.131]) by ironmsg09-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 10 Sep 2020 05:44:34 -0700 Received: from c-mansur-linux.qualcomm.com ([10.204.90.208]) by ironmsg02-blr.qualcomm.com with ESMTP; 10 Sep 2020 18:14:23 +0530 Received: by c-mansur-linux.qualcomm.com (Postfix, from userid 461723) id 5305E21D23; Thu, 10 Sep 2020 18:14:22 +0530 (IST) From: Mansur Alisha Shaik To: linux-media@vger.kernel.org, stanimir.varbanov@linaro.org Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, vgarodia@codeaurora.org, Mansur Alisha Shaik Subject: [PATCH v2 1/3] venus: core: handle race condititon for core ops Date: Thu, 10 Sep 2020 18:14:14 +0530 Message-Id: <1599741856-16239-2-git-send-email-mansur@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1599741856-16239-1-git-send-email-mansur@codeaurora.org> References: <1599741856-16239-1-git-send-email-mansur@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org For core ops we are having only write protect but there is no read protect, because of this in multthreading and concurrency, one CPU core is reading without wait which is causing the NULL pointer dereferece crash. one such scenario is as show below, where in one CPU core, core->ops becoming NULL and in another CPU core calling core->ops->session_init(). CPU: core-7: Call trace: hfi_session_init+0x180/0x1dc [venus_core] vdec_queue_setup+0x9c/0x364 [venus_dec] vb2_core_reqbufs+0x1e4/0x368 [videobuf2_common] vb2_reqbufs+0x4c/0x64 [videobuf2_v4l2] v4l2_m2m_reqbufs+0x50/0x84 [v4l2_mem2mem] v4l2_m2m_ioctl_reqbufs+0x2c/0x38 [v4l2_mem2mem] v4l_reqbufs+0x4c/0x5c __video_do_ioctl+0x2b0/0x39c CPU: core-0: Call trace: venus_shutdown+0x98/0xfc [venus_core] venus_sys_error_handler+0x64/0x148 [venus_core] process_one_work+0x210/0x3d0 worker_thread+0x248/0x3f4 kthread+0x11c/0x12c Signed-off-by: Mansur Alisha Shaik Acked-by: Stanimir Varbanov --- Changes in V2: - Addressed review comments by stan by validating on top - of https://lore.kernel.org/patchwork/project/lkml/list/?series=455962 drivers/media/platform/qcom/venus/hfi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/qcom/venus/hfi.c b/drivers/media/platform/qcom/venus/hfi.c index a59022a..3137071 100644 --- a/drivers/media/platform/qcom/venus/hfi.c +++ b/drivers/media/platform/qcom/venus/hfi.c @@ -195,7 +195,7 @@ EXPORT_SYMBOL_GPL(hfi_session_create); int hfi_session_init(struct venus_inst *inst, u32 pixfmt) { struct venus_core *core = inst->core; - const struct hfi_ops *ops = core->ops; + const struct hfi_ops *ops; int ret; if (inst->state != INST_UNINIT) @@ -204,10 +204,13 @@ int hfi_session_init(struct venus_inst *inst, u32 pixfmt) inst->hfi_codec = to_codec_type(pixfmt); reinit_completion(&inst->done); + mutex_lock(&core->lock); + ops = core->ops; ret = ops->session_init(inst, inst->session_type, inst->hfi_codec); if (ret) return ret; + mutex_unlock(&core->lock); ret = wait_session_msg(inst); if (ret) return ret;