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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 E2276C10F14 for ; Thu, 10 Oct 2019 08:55:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BA10221920 for ; Thu, 10 Oct 2019 08:55:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570697724; bh=2L6z+YucNVtGSXTpTVYqs4wYjrBZz8a4o9AYczD3IjE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lUiIXYJ20p0dLY0MfnXRxKp5hAtMDex2Jm7erLzCJ+l1qPnD/IsitaLsaKuhdsxvz KvWBV6HP9WfVi+Rz+NfJMuQspT5hyMWupl7taNoZD8rj21pKlT1H5feDKns6ln+C+5 n4+RmkYiHA6UWnGwPDkPQcBWzlpMqEvsY9Mjj2pM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389822AbfJJIt3 (ORCPT ); Thu, 10 Oct 2019 04:49:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:56076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389816AbfJJIt3 (ORCPT ); Thu, 10 Oct 2019 04:49:29 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 393DD2190F; Thu, 10 Oct 2019 08:49:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570697367; bh=2L6z+YucNVtGSXTpTVYqs4wYjrBZz8a4o9AYczD3IjE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NsrHM7IltGWCClouiMdwlq7ZW6cT8vg15O5mv1e2fnVLaexdrd6/vDpLzZZ5RXO58 0HmKicjtn+y9/sVhkB6WmUX2duo2JvXhtKVIKlf5PV8F6jSxWtNcbCNbvImPJFdB74 z/8VhqO099UjUK1Sr/ILi7IxBZJb3/aBZjFWw0tM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chris Wilson , Tvrtko Ursulin , Sasha Levin Subject: [PATCH 4.19 087/114] drm/i915/userptr: Acquire the page lock around set_page_dirty() Date: Thu, 10 Oct 2019 10:36:34 +0200 Message-Id: <20191010083612.658211813@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191010083544.711104709@linuxfoundation.org> References: <20191010083544.711104709@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chris Wilson [ Upstream commit cb6d7c7dc7ff8cace666ddec66334117a6068ce2 ] set_page_dirty says: For pages with a mapping this should be done under the page lock for the benefit of asynchronous memory errors who prefer a consistent dirty state. This rule can be broken in some special cases, but should be better not to. Under those rules, it is only safe for us to use the plain set_page_dirty calls for shmemfs/anonymous memory. Userptr may be used with real mappings and so needs to use the locked version (set_page_dirty_lock). Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203317 Fixes: 5cc9ed4b9a7a ("drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl") Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: stable@vger.kernel.org Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20190708140327.26825-1-chris@chris-wilson.co.uk Signed-off-by: Sasha Levin --- drivers/gpu/drm/i915/i915_gem_userptr.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index 2c9b284036d10..e13ea2ecd669c 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -692,7 +692,15 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj, for_each_sgt_page(page, sgt_iter, pages) { if (obj->mm.dirty) - set_page_dirty(page); + /* + * As this may not be anonymous memory (e.g. shmem) + * but exist on a real mapping, we have to lock + * the page in order to dirty it -- holding + * the page reference is not sufficient to + * prevent the inode from being truncated. + * Play safe and take the lock. + */ + set_page_dirty_lock(page); mark_page_accessed(page); put_page(page); -- 2.20.1