From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A5FEC36E488 for ; Mon, 1 Jun 2026 10:47:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780310823; cv=none; b=BG8YXgtjZNpEot29F5pYePeSSnX7/4n65bFJwl1tKpns8OwM69wcTPfkJPoSX6bg2XEehJSWf2/VzX0iaCEYBA/Qgt3QZFZ1jGfMNb/pyurblowwp3fZGtuwmTwJAtWZtcZpVsTEZ5JbtEXQBLW+rX7Vz3o/4Yz9xgA5ox4ekuo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780310823; c=relaxed/simple; bh=G/ZuPG5aUH+2gEMdd7aL9EhmbAOAuZWxu6GJ5kQuOO0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NHh6JOwqWS+7lMrw5EEMxji8oyJ2GZUVn6D/7Bzrd/0qWGdMx9r3UAYQiFwUET56TlfkVL53ZYUVKc+QkAxO1cVH7/X98OM9jvPeDtvWX/OgHKUYdr8UpdMRx0FTB+uAivR2nUToDUmsd1yTWYT5P1Nh0dcKkn8bjzTyo7qB7C4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ErHsC3q1; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ErHsC3q1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1780310822; x=1811846822; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=G/ZuPG5aUH+2gEMdd7aL9EhmbAOAuZWxu6GJ5kQuOO0=; b=ErHsC3q10kFtHuXnoar1MKA4oAojIN96COrKH21QV/ABd22oH9UWpQ3C k/cImYducHfqYla+ex/+oT1kHHNwyAsGImgjB3TLhtTSsS/0YwCOGJV8g qHblQ8AYdq41sxFmkDPDDPrgxHVZ4PNiNRtiB7eAt6ZCD5dxm6QZFZhX6 ywDbxq1nFPQ3ifmizrkYK3uvOyocZ7tTQ7c8o+T89e+qls2TtsHJT25i3 /erjeMcy/yQFDWTWpkowYXCbYWAJaJCl+TVMgbuQSvabYi8lRHSGr9lDk 4EJkRqqF6vfgUJ8iRHlssdqyAiZlwN/8mSKpuld36EMIpLec4rLkbvLt8 Q==; X-CSE-ConnectionGUID: jjMQiVIoSBiV9yzG2BKY1A== X-CSE-MsgGUID: wZW6ERBgQiCMhEaRii6WFQ== X-IronPort-AV: E=McAfee;i="6800,10657,11803"; a="81178428" X-IronPort-AV: E=Sophos;i="6.24,181,1774335600"; d="scan'208";a="81178428" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2026 03:47:01 -0700 X-CSE-ConnectionGUID: z6RNbQ3NS6+9dICzzjir+w== X-CSE-MsgGUID: Bi6oWTQ/QCqjy7elmoyqHw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,181,1774335600"; d="scan'208";a="243659033" Received: from dhhellew-desk2.ger.corp.intel.com (HELO [10.245.245.132]) ([10.245.245.132]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2026 03:46:59 -0700 Message-ID: Date: Mon, 1 Jun 2026 11:46:56 +0100 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/xe: Fix UAF in xe_gem_prime_import() on attach failure To: Nitin Gote , intel-xe@lists.freedesktop.org, =?UTF-8?Q?christian_K=C3=B6nig?= , =?UTF-8?Q?Christian_K=C3=B6nig?= Cc: stable@vger.kernel.org, Thomas Hellstrom , Matthew Brost References: <20260601101536.1333480-2-nitin.r.gote@intel.com> Content-Language: en-GB From: Matthew Auld In-Reply-To: <20260601101536.1333480-2-nitin.r.gote@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 01/06/2026 11:15, Nitin Gote wrote: > xe_dma_buf_create_obj() creates the importer BO with obj->resv > pointing at the exporter's dma_buf->resv. When dma_buf_dynamic_attach() > fails, no dma_buf reference is held so the exporter can be freed > immediately. Since ttm_bo_release() now always defers cleanup for > ttm_bo_type_sg BOs to the TTM workqueue, the worker later calls > dma_resv_lock() on the already-freed exporter resv, causing a UAF. > > Reset obj->resv to the BO's private _resv before calling xe_bo_put() > in the error path. The BO is not yet published (attach failed) and > carries no fences, so the switch is safe. > > Observed with igt@xe_live_ktest@xe_dma_buf_kunit on BMG (QEMU): > > Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b9c > Workqueue: ttm ttm_bo_delayed_delete [ttm] > RIP: 0010:mutex_can_spin_on_owner+0x3f/0xc0 > Call Trace: > > ? __ww_mutex_lock.constprop.0+0x2dd/0x18e0 > ? ttm_bo_delayed_delete+0x41/0xc0 [ttm] > ww_mutex_lock+0x3c/0xb0 > ttm_bo_delayed_delete+0x41/0xc0 [ttm] > process_one_work+0x239/0x740 > worker_thread+0x200/0x3f0 > kthread+0x10d/0x150 > ret_from_fork+0x3bd/0x470 > ret_from_fork_asm+0x1a/0x30 > > > Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/work_items/8023 > Fixes: d99fbd9aab62 ("drm/ttm: Always take the bo delayed cleanup path for imported bos") > Cc: stable@vger.kernel.org # v6.8+ > Cc: Thomas Hellstrom > Cc: Matthew Brost > Cc: Matthew Auld > Signed-off-by: Nitin Gote > --- > drivers/gpu/drm/xe/xe_dma_buf.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c > index 8a920e58245c..6d944bd4065c 100644 > --- a/drivers/gpu/drm/xe/xe_dma_buf.c > +++ b/drivers/gpu/drm/xe/xe_dma_buf.c > @@ -384,6 +384,14 @@ struct drm_gem_object *xe_gem_prime_import(struct drm_device *dev, > > attach = dma_buf_dynamic_attach(dma_buf, dev->dev, attach_ops, obj); > if (IS_ERR(attach)) { > + /* > + * The BO was created with resv = dma_buf->resv (exporter's > + * resv). Since attach failed, no dma_buf reference is held and > + * the exporter may be freed before TTM's delayed_delete worker > + * runs. Switch to the BO's own resv to prevent a UAF when > + * ttm_bo_delayed_delete() tries to lock the stale pointer. > + */ > + obj->resv = &obj->_resv; +Christian, does amdgpu not have the type of same issue here? Also any thoughts here? > xe_bo_put(gem_to_xe_bo(obj)); > return ERR_CAST(attach); > }