From patchwork Mon Jun 1 22:03:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 64171 Received: from vger.kernel.org ([23.128.96.18]) by www.linuxtv.org with esmtp (Exim 4.92) (envelope-from ) id 1jfsTP-00E0tB-ME; Mon, 01 Jun 2020 22:00:00 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728817AbgFAWDs (ORCPT + 1 other); Mon, 1 Jun 2020 18:03:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47516 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728488AbgFAWDr (ORCPT ); Mon, 1 Jun 2020 18:03:47 -0400 Received: from mail-pl1-x641.google.com (mail-pl1-x641.google.com [IPv6:2607:f8b0:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 561F5C08C5C0 for ; Mon, 1 Jun 2020 15:03:47 -0700 (PDT) Received: by mail-pl1-x641.google.com with SMTP id v24so482019plo.6 for ; Mon, 01 Jun 2020 15:03:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=XFnIQB7ncVF63T1pY2NMmD5MUjtRKH/Cyt/vduuOCr4=; b=fek/fKkwjOdhsv+J8geTqfhekmIfVg31GBFgDaJGfViiSS3F/TsrEDBUE9wVv/9R8E SLECz+XjlLL63WPLyFxiSgONAHsFBoColGWxAzWM9st+Pt4+fuDZvusd10ecebte6xxm cZP+Te8MKz3ySAe3gVd2jr865slvk2yVvi9Hg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=XFnIQB7ncVF63T1pY2NMmD5MUjtRKH/Cyt/vduuOCr4=; b=NWu/lNhUoIPc41e++yM2ZBPsxoPYnw2bQKyHVY/r+XnEIAwZfmyNs/brljJgR/XXzC YQYp68/fnkR4dkfFsEE13EjKvNjGtZu/JCCFbHHUa3AW/FNGkOcsJva8qmy5bhx57i9i Lp+uHJm6ud1TFwDONpMuDSeXIGm6ayPisZ8jWfzVYGtaiXuyFwtlsxwdLXKBX0Zy9G7r Mg4zMBG/W9JMR6aX94bioLxZi0gJ8tovXS+zDk67hM2yjdexX+ClQcvKOGoCRbiPG54V joG1ls+lnRi+dK0u2FAYRijUVH67JAQ+KWHU4nMY5uI8Rbfdf9YpMzy8IEeFCs3N37PK qb/g== X-Gm-Message-State: AOAM531rOZ8AAdLvxi2Vm5M1uOaulZtezNZTbLB81VSFRRRS9PdtBeoq UmiCqGKsMPMA6OtZtAy8ncQi5A== X-Google-Smtp-Source: ABdhPJweeLR8G4rZkKaY74PZV+ncoWYY84wN8268AueoBMTYcuSWzeDoqapxC9otqNOiOJ4igNbeRg== X-Received: by 2002:a17:902:7041:: with SMTP id h1mr22988066plt.169.1591049026875; Mon, 01 Jun 2020 15:03:46 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id 67sm346948pfg.84.2020.06.01.15.03.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Jun 2020 15:03:46 -0700 (PDT) From: Douglas Anderson To: amasule@codeaurora.org, stanimir.varbanov@linaro.org Cc: swboyd@chromium.org, jkardatzke@google.com, mka@chromium.org, Douglas Anderson , Andy Gross , Bjorn Andersson , Mauro Carvalho Chehab , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Subject: [RFC PATCH] media: venus: Fix NULL pointer dereference in core selection Date: Mon, 1 Jun 2020 15:03:22 -0700 Message-Id: <20200601150314.RFC.1.I1e40623bbe8fa43ff1415fc273cba66503b9b048@changeid> X-Mailer: git-send-email 2.27.0.rc2.251.g90737beb825-goog MIME-Version: 1.0 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-LSpam-Score: -2.5 (--) X-LSpam-Report: No, score=-2.5 required=5.0 tests=BAYES_00=-1.9,DKIMWL_WL_HIGH=0.001,DKIM_SIGNED=0.1,DKIM_VALID=-0.1,DKIM_VALID_AU=-0.1,HEADER_FROM_DIFFERENT_DOMAINS=0.5,MAILING_LIST_MULTI=-1 autolearn=ham autolearn_force=no The newly-introduced function min_loaded_core() iterates over all of the venus instances an tries to figure out how much load each instance is putting on each core. Not all instances, however, might be fully initialized. Specifically the "codec_freq_data" is initialized as part of vdec_queue_setup(), but an instance may already be in the list of all instances before that time. Let's band-aid this by checking to see if codec_freq_data is NULL before dereferencing. NOTE: without this fix I was running into a crash. Specifically there were two venus instances. One was doing start_streaming. The other was midway through queue_setup but hadn't yet gotten to initting "codec_freq_data". Fixes: eff82f79c562 ("media: venus: introduce core selection") Signed-off-by: Douglas Anderson --- I'm not massively happy about this commit but it's the best I could come up with without being much more of an expert in the venus codec. If someone has a better patch then please just consider this one to be a bug report and feel free to submit a better fix! :-) In general I wonder a little bit about whether it's safe to be peeking at all the instances without grabbing the "inst->lock" on each one. I guess it is since we do it both here and in load_scale_v4() but I don't know why. One thought I had was that we could fully avoid accessing the other instances, at least in min_loaded_core(), by just keeping track of "core1_load" and "core2_load" in "struct venus_core". Whenever we add a new instance we could add to the relevant variables and whenever we release an instance we could remove. Such a change seems cleaner but would require someone to test to make sure we didn't miss any case (AKA we always properly added/removed our load from the globals). drivers/media/platform/qcom/venus/pm_helpers.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/platform/qcom/venus/pm_helpers.c b/drivers/media/platform/qcom/venus/pm_helpers.c index abf93158857b..a1d998f62cf2 100644 --- a/drivers/media/platform/qcom/venus/pm_helpers.c +++ b/drivers/media/platform/qcom/venus/pm_helpers.c @@ -496,6 +496,8 @@ min_loaded_core(struct venus_inst *inst, u32 *min_coreid, u32 *min_load) list_for_each_entry(inst_pos, &core->instances, list) { if (inst_pos == inst) continue; + if (!inst_pos->clk_data.codec_freq_data) + continue; vpp_freq = inst_pos->clk_data.codec_freq_data->vpp_freq; coreid = inst_pos->clk_data.core_id;