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=-9.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 5F5CBC6786F for ; Tue, 30 Oct 2018 13:27:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2685920827 for ; Tue, 30 Oct 2018 13:27:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="fF8d9uuu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2685920827 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1728104AbeJ3WUe (ORCPT ); Tue, 30 Oct 2018 18:20:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:51422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727576AbeJ3WUe (ORCPT ); Tue, 30 Oct 2018 18:20:34 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A839F2075D; Tue, 30 Oct 2018 13:27:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1540906026; bh=qvTMp9NME4T1wpuT2GnKguX55scpDm65r+lRvZMiHHo=; h=From:To:Cc:Subject:Date:From; b=fF8d9uuujVW92iU4s8EBRUe1+6TI4ISDyjINRB1cL5tx335dCDiZRl2TwLp3SrH/W 6RDYihbmO+lAxvAAJ86e7ImKbjV99y3Iyc+09ATetnMsQFs6TCCFwbM4nL75ChkzqQ TaD+NYvOzT/cWRLeLDcj6N1emn0CkZrA+CRf72C0= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Tomi Valkeinen , Sasha Levin Subject: [PATCH AUTOSEL 4.18 01/33] drm: fix use of freed memory in drm_mode_setcrtc Date: Tue, 30 Oct 2018 09:26:25 -0400 Message-Id: <20181030132657.217970-1-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tomi Valkeinen [ Upstream commit 064253c1c0625efd0362a0b7ecdbe8bee2a2904d ] drm_mode_setcrtc() retries modesetting in case one of the functions it calls returns -EDEADLK. connector_set, mode and fb are freed before retrying, but they are not set to NULL. This can cause drm_mode_setcrtc() to use those variables. For example: On the first try __drm_mode_set_config_internal() returns -EDEADLK. connector_set, mode and fb are freed. Next retry starts, and drm_modeset_lock_all_ctx() returns -EDEADLK, and we jump to 'out'. The code will happily try to release all three again. This leads to crashes of different kinds, depending on the sequence the EDEADLKs happen. Fix this by setting the three variables to NULL at the start of the retry loop. Signed-off-by: Tomi Valkeinen Reviewed-by: Ville Syrjälä Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180917110054.4053-1-tomi.valkeinen@ti.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_crtc.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index 98a36e6c69ad..bd207857a964 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -560,9 +560,9 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, struct drm_mode_crtc *crtc_req = data; struct drm_crtc *crtc; struct drm_plane *plane; - struct drm_connector **connector_set = NULL, *connector; - struct drm_framebuffer *fb = NULL; - struct drm_display_mode *mode = NULL; + struct drm_connector **connector_set, *connector; + struct drm_framebuffer *fb; + struct drm_display_mode *mode; struct drm_mode_set set; uint32_t __user *set_connectors_ptr; struct drm_modeset_acquire_ctx ctx; @@ -591,6 +591,10 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data, mutex_lock(&crtc->dev->mode_config.mutex); drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE); retry: + connector_set = NULL; + fb = NULL; + mode = NULL; + ret = drm_modeset_lock_all_ctx(crtc->dev, &ctx); if (ret) goto out; -- 2.17.1