From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.16]) (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 5EDEC38F239 for ; Mon, 1 Jun 2026 09:40:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780306830; cv=none; b=Ftc3jU+yqnpo4K+8TUhJZkkwWURi25aQ6voXzYrxdnwYv0jg/A3ps/hWd/xJQ+CSD288s24QSu/oYo4Zl4jKRwPATDBJZAG6gQsu6c63igWpBDnrZsGLo1vzl7PoeT/mMv+E+VIWPY4viIDV74NHkkvdW3B/rGbywSujRK9A/p4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780306830; c=relaxed/simple; bh=+RSiV4t9ZMPDIDecXW8eTPPICHYbj/MQhsKjjWhoYsQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KZWfIdo54Bp8FQrbmNBKq/lGugUq6rwhwPiTBHV5/LLgvGD+MA5urUY1zyOjO9CiBEQ2Usm+0n9OtEn6Sz0qqbuLcUOqQX/OxHzD7+i/PiYTgivI8xBZSfJDj4MiB0pd7UiHkpSnXT+ySKs3x/3P9cQnRidiOow7fmOJxm9DyoA= 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=T6l/voAi; arc=none smtp.client-ip=192.198.163.16 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="T6l/voAi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1780306828; x=1811842828; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=+RSiV4t9ZMPDIDecXW8eTPPICHYbj/MQhsKjjWhoYsQ=; b=T6l/voAiKBBAwYTC2983HeH1286gMa4dbgJM+Tnvl66spsv4hBgTWDPg 1L/BYMkQen0FOoGrgsVnd98CmwLcM0oBGeHcCfWHeFSIATA88Iyl/j19Q ti8QTCnVPNMSY+qLnP1qtzOpbc4R9ZuRd353inEsMcj77SJbfpzQTbJP1 ljhIPu4zHjMadQLgs+mQOVP6EFw2FzVpvHnq7OKjOMOU2HYxISiwjOm15 RDCysszdnyKRHzDZi5XSwRRHNHvS7HYpLdgjjsqJirneXJh0iSzcdm/ft i8OyDwrh/qQqHISlg3BU4gPVAH8oiTMb+O8wA9xFXMwceiB5cQzMHIFeD A==; X-CSE-ConnectionGUID: adz3J4x2QRmXtsqcL4iMSg== X-CSE-MsgGUID: D24/tZJrRJaaMifgXvlVig== X-IronPort-AV: E=McAfee;i="6800,10657,11803"; a="68595816" X-IronPort-AV: E=Sophos;i="6.24,181,1774335600"; d="scan'208";a="68595816" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2026 02:40:28 -0700 X-CSE-ConnectionGUID: 9BJz7sp5Smmqb/5ZXjUfGg== X-CSE-MsgGUID: b9cZHzXPTa29C6uRfpUttw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,181,1774335600"; d="scan'208";a="239344266" Received: from nitin-super-server.iind.intel.com ([10.190.238.72]) by fmviesa010.fm.intel.com with ESMTP; 01 Jun 2026 02:40:26 -0700 From: Nitin Gote To: intel-xe@lists.freedesktop.org Cc: Nitin Gote , stable@vger.kernel.org, Thomas Hellstrom , Matthew Brost , Matthew Auld Subject: [PATCH] drm/xe: Fix UAF in xe_gem_prime_import() on attach failure Date: Mon, 1 Jun 2026 15:45:37 +0530 Message-ID: <20260601101536.1333480-2-nitin.r.gote@intel.com> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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; xe_bo_put(gem_to_xe_bo(obj)); return ERR_CAST(attach); } -- 2.50.1