From nobody Mon Jun 22 18:10:30 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2B46C433EF for ; Fri, 18 Mar 2022 19:50:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240423AbiCRTwB (ORCPT ); Fri, 18 Mar 2022 15:52:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230302AbiCRTv7 (ORCPT ); Fri, 18 Mar 2022 15:51:59 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0382D2E8435 for ; Fri, 18 Mar 2022 12:50:32 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: bbeckett) with ESMTPSA id 9A2AE1F45B08 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1647633030; bh=9bigV/sYB4FUqshAYJdxs+cHARVqE00dOiOAg3Egs9Y=; h=From:To:Cc:Subject:Date:From; b=gDqPOrSjJ86k3/PKnd8PPM1RMLwNcZ91aYkmOXXsSFBIn8gTvQ/FZXK08Katx/ZiZ I8O3uG04Kq3RwGkO2127RrkM5BKVP+aiLSBRF1dneFE5QTaZi7yoOEkkviTJ9vLrSz 7qHjX7+sDOKZz7JLeqodv+QtFd/kTxMQ3s9aHnOv4xJoH7/FdA0qzwmlf0CipF3zcB uv64JtT1fhiJUGvraQaRCDlgfhio7TD2iX6Zg1jrd3TqVQZKxJQuMwibHnvQC3CWlC DE0qHvObvxA1dcS4sL96zUgi6JgoKE1EUEwjhDFT6+TomJpFjbd0L0kdTXNO3L46df edaJbSf6GkoHg== From: Robert Beckett To: dri-devel@lists.freedesktop.org, Christian Koenig , Huang Rui , David Airlie , Daniel Vetter , Matthew Auld Cc: Robert Beckett , linux-kernel@vger.kernel.org Subject: [PATCH] drm/ttm: fix potential null ptr deref in when mem space alloc fails Date: Fri, 18 Mar 2022 19:50:04 +0000 Message-Id: <20220318195004.416539-1-bob.beckett@collabora.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" when allocating a resource in place it is common to free the buffer's resource, then allocate a new resource in a different placement. e.g. amdgpu_bo_create_kernel_at calls ttm_resource_free, then calls ttm_bo_mem_space. In this situation, bo->resource will be null as it is cleared during the initial freeing of the previous resource. This leads to a null deref. Fixes: d3116756a710 (drm/ttm: rename bo->mem and make it a pointer) Signed-off-by: Robert Beckett --- drivers/gpu/drm/ttm/ttm_bo.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index db3dc7ef5382..62b29ee7d040 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -875,7 +875,7 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo, } =20 error: - if (bo->resource->mem_type =3D=3D TTM_PL_SYSTEM && !bo->pin_count) + if (bo->resource && bo->resource->mem_type =3D=3D TTM_PL_SYSTEM && !bo->p= in_count) ttm_bo_move_to_lru_tail_unlocked(bo); =20 return ret; --=20 2.25.1