From patchwork Thu Jan 18 14:58:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris BREZILLON X-Patchwork-Id: 10173501 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 99AB7602DC for ; Thu, 18 Jan 2018 14:58:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 87D5120500 for ; Thu, 18 Jan 2018 14:58:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 77E3B223A0; Thu, 18 Jan 2018 14:58:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 2C62220500 for ; Thu, 18 Jan 2018 14:58:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4179F6E609; Thu, 18 Jan 2018 14:58:27 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.free-electrons.com (mail.free-electrons.com [62.4.15.54]) by gabe.freedesktop.org (Postfix) with ESMTP id 9D42F6E609 for ; Thu, 18 Jan 2018 14:58:25 +0000 (UTC) Received: by mail.free-electrons.com (Postfix, from userid 110) id EBE2D20913; Thu, 18 Jan 2018 15:58:23 +0100 (CET) Received: from localhost.localdomain (LStLambert-657-1-97-87.w90-63.abo.wanadoo.fr [90.63.216.87]) by mail.free-electrons.com (Postfix) with ESMTPSA id B4CD4208CD; Thu, 18 Jan 2018 15:58:23 +0100 (CET) From: Boris Brezillon To: David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, Eric Anholt Subject: [PATCH v2] drm/vc4: Fix NULL pointer dereference in vc4_save_hang_state() Date: Thu, 18 Jan 2018 15:58:21 +0100 Message-Id: <20180118145821.22344-1-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 2.11.0 Cc: Boris Brezillon , stable@vger.kernel.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP When saving BOs in the hang state we skip one entry of the kernel_state->bo[] array, thus leaving it to NULL. This leads to a NULL pointer dereference when, later in this function, we iterate over all BOs to check their ->madv state. Fixes: ca26d28bbaa3 ("drm/vc4: improve throughput by pipelining binning and rendering jobs") Cc: Signed-off-by: Boris Brezillon --- Changes in v2: - Get rid of prev_idx an replace it by k which is indepently incremented every time a new object is added to kernel_state->bo[]. - Add a WARN_ON_ONCE() when final value of k is inconsistent --- drivers/gpu/drm/vc4/vc4_gem.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c index 6c32c89a83a9..3216f12052fe 100644 --- a/drivers/gpu/drm/vc4/vc4_gem.c +++ b/drivers/gpu/drm/vc4/vc4_gem.c @@ -146,7 +146,7 @@ vc4_save_hang_state(struct drm_device *dev) struct vc4_exec_info *exec[2]; struct vc4_bo *bo; unsigned long irqflags; - unsigned int i, j, unref_list_count, prev_idx; + unsigned int i, j, k, unref_list_count; kernel_state = kcalloc(1, sizeof(*kernel_state), GFP_KERNEL); if (!kernel_state) @@ -182,7 +182,7 @@ vc4_save_hang_state(struct drm_device *dev) return; } - prev_idx = 0; + k = 0; for (i = 0; i < 2; i++) { if (!exec[i]) continue; @@ -197,7 +197,7 @@ vc4_save_hang_state(struct drm_device *dev) WARN_ON(!refcount_read(&bo->usecnt)); refcount_inc(&bo->usecnt); drm_gem_object_get(&exec[i]->bo[j]->base); - kernel_state->bo[j + prev_idx] = &exec[i]->bo[j]->base; + kernel_state->bo[k++] = &exec[i]->bo[j]->base; } list_for_each_entry(bo, &exec[i]->unref_list, unref_head) { @@ -205,12 +205,12 @@ vc4_save_hang_state(struct drm_device *dev) * because they are naturally unpurgeable. */ drm_gem_object_get(&bo->base.base); - kernel_state->bo[j + prev_idx] = &bo->base.base; - j++; + kernel_state->bo[k++] = &bo->base.base; } - prev_idx = j + 1; } + WARN_ON_ONCE(k != state->bo_count); + if (exec[0]) state->start_bin = exec[0]->ct0ca; if (exec[1])