From patchwork Wed Sep 16 08:49:32 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: 292834 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA54BC433E2 for ; Wed, 16 Sep 2020 08:50:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7186F20872 for ; Wed, 16 Sep 2020 08:50:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726695AbgIPIuJ (ORCPT ); Wed, 16 Sep 2020 04:50:09 -0400 Received: from alexa-out.qualcomm.com ([129.46.98.28]:57361 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726612AbgIPIt7 (ORCPT ); Wed, 16 Sep 2020 04:49:59 -0400 Received: from ironmsg07-lv.qualcomm.com (HELO ironmsg07-lv.qulacomm.com) ([10.47.202.151]) by alexa-out.qualcomm.com with ESMTP; 16 Sep 2020 01:49:58 -0700 Received: from ironmsg02-blr.qualcomm.com ([10.86.208.131]) by ironmsg07-lv.qulacomm.com with ESMTP/TLS/AES256-SHA; 16 Sep 2020 01:49:56 -0700 Received: from c-mansur-linux.qualcomm.com ([10.204.90.208]) by ironmsg02-blr.qualcomm.com with ESMTP; 16 Sep 2020 14:19:40 +0530 Received: by c-mansur-linux.qualcomm.com (Postfix, from userid 461723) id C85EE21D3B; Wed, 16 Sep 2020 14:19:39 +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 v4 1/3] venus: core: handle race condititon for core ops Date: Wed, 16 Sep 2020 14:19:32 +0530 Message-Id: <1600246174-31802-2-git-send-email-mansur@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1600246174-31802-1-git-send-email-mansur@codeaurora.org> References: <1600246174-31802-1-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 V4: - Addressed review comments by Stan in patch series https://lore.kernel.org/patchwork/patch/1303678/ and combining this change along with shutdown callback as we are facing race conditions with shutdown callback drivers/media/platform/qcom/venus/hfi.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/qcom/venus/hfi.c b/drivers/media/platform/qcom/venus/hfi.c index a59022a..58d4c06 100644 --- a/drivers/media/platform/qcom/venus/hfi.c +++ b/drivers/media/platform/qcom/venus/hfi.c @@ -195,19 +195,34 @@ 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 core shutdown is in progress or if we are in system + * recovery, return an error as during system error recovery + * session_init() can't pass successfully + */ + mutex_lock(&core->lock); + if (!core->ops || core->sys_error) { + mutex_unlock(&core->lock); + return -EIO; + } + mutex_unlock(&core->lock); + if (inst->state != INST_UNINIT) return -EINVAL; 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;