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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 D48C8C3A5A7 for ; Tue, 3 Sep 2019 16:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC7722339D for ; Tue, 3 Sep 2019 16:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567528836; bh=I4pIN+mEaSuT392rHzLLHJemMjxOuk9bFdVUaNZkqDw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ROwk4RGKTOIeFKOvC5f/lXZktHfBraxHO7xLFuJ3jmUunsNhbMr2tcOj27rtMxvn9 msThRW1Yt6hcLq3zE1VsQ/V+hLjRyVK9zRRe057RGQAXreVc1vG+ewn6ZRJ9oylL1n GCmHTc176l1QGd/Xo/6Y0jVlI1lI8sEHKJEljWpk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730258AbfICQZF (ORCPT ); Tue, 3 Sep 2019 12:25:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:44720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730237AbfICQZC (ORCPT ); Tue, 3 Sep 2019 12:25:02 -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 91A702343A; Tue, 3 Sep 2019 16:25:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567527901; bh=I4pIN+mEaSuT392rHzLLHJemMjxOuk9bFdVUaNZkqDw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U7tKk0i45ekBuKenlqD6dNwEImjyPsTyHQuQQ50S/mlwnSQ0LSFtjpscQr3XzaM04 6+8HYpsAtH+Gq0tIDU+ThjYrUtYSZVsOlDXEFvId0Rc5zZqyMjlO8LbQGDYPGWy/iL P9OKmsjtc+T74/Pn4HMl313ZLvA1oH+RC+iYvdVw= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Chris Wilson , Tvrtko Ursulin , Jani Nikula , Sasha Levin , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 5.2 13/23] drm/i915/userptr: Acquire the page lock around set_page_dirty() Date: Tue, 3 Sep 2019 12:24:14 -0400 Message-Id: <20190903162424.6877-13-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190903162424.6877-1-sashal@kernel.org> References: <20190903162424.6877-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chris Wilson [ Upstream commit aa56a292ce623734ddd30f52d73f527d1f3529b5 ] 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") References: 6dcc693bc57f ("ext4: warn when page is dirtied without buffers") 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 (cherry picked from commit cb6d7c7dc7ff8cace666ddec66334117a6068ce2) Signed-off-by: Jani Nikula 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 8079ea3af1039..b1fc15c7f5997 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -678,7 +678,15 @@ 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