From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752840AbeCUTHD (ORCPT ); Wed, 21 Mar 2018 15:07:03 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54549 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752637AbeCUTHA (ORCPT ); Wed, 21 Mar 2018 15:07:00 -0400 From: Colin King To: Zhenyu Wang , Zhi Wang , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm/i915/gvt: don't dereference 'workload' before null checking it Date: Wed, 21 Mar 2018 19:06:53 +0000 Message-Id: <20180321190653.3829-1-colin.king@canonical.com> X-Mailer: git-send-email 2.15.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King The pointer workload is dereferenced before it is null checked, hence there is a potential for a null pointer dereference on workload. Fix this by only dereferencing workload after it is null checked. Detected by CoverityScan, CID#1466017 ("Dereference before null check") Fixes: fa3dd623e559 ("drm/i915/gvt: keep oa config in shadow ctx") Signed-off-by: Colin Ian King --- drivers/gpu/drm/i915/gvt/scheduler.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c index 068126404151..f3010e365a48 100644 --- a/drivers/gpu/drm/i915/gvt/scheduler.c +++ b/drivers/gpu/drm/i915/gvt/scheduler.c @@ -60,9 +60,9 @@ static void set_context_pdp_root_pointer( static void sr_oa_regs(struct intel_vgpu_workload *workload, u32 *reg_state, bool save) { - struct drm_i915_private *dev_priv = workload->vgpu->gvt->dev_priv; - u32 ctx_oactxctrl = dev_priv->perf.oa.ctx_oactxctrl_offset; - u32 ctx_flexeu0 = dev_priv->perf.oa.ctx_flexeu0_offset; + struct drm_i915_private *dev_priv; + u32 ctx_oactxctrl; + u32 ctx_flexeu0; int i = 0; u32 flex_mmio[] = { i915_mmio_reg_offset(EU_PERF_CNTL0), @@ -77,6 +77,10 @@ static void sr_oa_regs(struct intel_vgpu_workload *workload, if (!workload || !reg_state || workload->ring_id != RCS) return; + dev_priv = workload->vgpu->gvt->dev_priv; + ctx_oactxctrl = dev_priv->perf.oa.ctx_oactxctrl_offset; + ctx_flexeu0 = dev_priv->perf.oa.ctx_flexeu0_offset; + if (save) { workload->oactxctrl = reg_state[ctx_oactxctrl + 1]; -- 2.15.1