From mboxrd@z Thu Jan 1 00:00:00 1970 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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 BBE17C28CF6 for ; Tue, 24 Jul 2018 22:54:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 71F0420856 for ; Tue, 24 Jul 2018 22:54:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 71F0420856 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=anholt.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388897AbeGYADL (ORCPT ); Tue, 24 Jul 2018 20:03:11 -0400 Received: from anholt.net ([50.246.234.109]:38410 "EHLO anholt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388758AbeGYADL (ORCPT ); Tue, 24 Jul 2018 20:03:11 -0400 Received: from localhost (localhost [127.0.0.1]) by anholt.net (Postfix) with ESMTP id 0897310A1504; Tue, 24 Jul 2018 15:54:29 -0700 (PDT) X-Virus-Scanned: Debian amavisd-new at anholt.net Received: from anholt.net ([127.0.0.1]) by localhost (kingsolver.anholt.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id awSiCECw7zgo; Tue, 24 Jul 2018 15:54:27 -0700 (PDT) Received: from eliezer.anholt.net (localhost [127.0.0.1]) by anholt.net (Postfix) with ESMTP id B924810A053F; Tue, 24 Jul 2018 15:54:27 -0700 (PDT) Received: by eliezer.anholt.net (Postfix, from userid 1000) id 35CFD2FE4641; Tue, 24 Jul 2018 15:54:27 -0700 (PDT) From: Eric Anholt To: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, Lucas Stach , Eric Anholt Subject: [PATCH] drm/v3d: Fix a use-after-free race accessing the scheduler's fences. Date: Tue, 24 Jul 2018 15:54:27 -0700 Message-Id: <20180724225427.1407-1-eric@anholt.net> X-Mailer: git-send-email 2.18.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Once we push the job, the scheduler could run it and free it. So, if we want to reference their fences, we need to grab them before then. I haven't seen this happen in many days of conformance test runtime, but let's still close the race. Signed-off-by: Eric Anholt Fixes: 57692c94dcbe ("drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+") --- drivers/gpu/drm/v3d/v3d_drv.h | 5 +++++ drivers/gpu/drm/v3d/v3d_gem.c | 8 ++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h index 5042573e97f4..83c55ab6e1c0 100644 --- a/drivers/gpu/drm/v3d/v3d_drv.h +++ b/drivers/gpu/drm/v3d/v3d_drv.h @@ -204,6 +204,11 @@ struct v3d_exec_info { */ struct dma_fence *bin_done_fence; + /* Fence for when the scheduler considers the render to be + * done, for when the BOs reservations should be complete. + */ + struct dma_fence *render_done_fence; + struct kref refcount; /* This is the array of BOs that were looked up at the start of exec. */ diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c index e1fcbb4cd0ae..c98fbfbdb68e 100644 --- a/drivers/gpu/drm/v3d/v3d_gem.c +++ b/drivers/gpu/drm/v3d/v3d_gem.c @@ -209,7 +209,7 @@ v3d_flush_caches(struct v3d_dev *v3d) static void v3d_attach_object_fences(struct v3d_exec_info *exec) { - struct dma_fence *out_fence = &exec->render.base.s_fence->finished; + struct dma_fence *out_fence = exec->render_done_fence; struct v3d_bo *bo; int i; @@ -409,6 +409,7 @@ v3d_exec_cleanup(struct kref *ref) dma_fence_put(exec->render.done_fence); dma_fence_put(exec->bin_done_fence); + dma_fence_put(exec->render_done_fence); for (i = 0; i < exec->bo_count; i++) drm_gem_object_put_unlocked(&exec->bo[i]->base); @@ -574,6 +575,9 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, if (ret) goto fail_unreserve; + exec->render_done_fence = + dma_fence_get(&exec->render.base.s_fence->finished); + kref_get(&exec->refcount); /* put by scheduler job completion */ drm_sched_entity_push_job(&exec->render.base, &v3d_priv->sched_entity[V3D_RENDER]); @@ -587,7 +591,7 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, sync_out = drm_syncobj_find(file_priv, args->out_sync); if (sync_out) { drm_syncobj_replace_fence(sync_out, - &exec->render.base.s_fence->finished); + exec->render_done_fence); drm_syncobj_put(sync_out); } -- 2.18.0