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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 93685C2D0C1 for ; Thu, 19 Dec 2019 18:58:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A1A8206EC for ; Thu, 19 Dec 2019 18:58:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576781899; bh=Be1O2j7Z4b1WMstvecL4tEM81NqtYVosdwqztphEMZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2IG5t9oNpeEGbpdE6qEBj9XTxst8Bab30jSYkeAf+vy+oQkk3La0Mb0xPCZt2hmr+ q2wPcUljnh3X9zSPNKFJNmJHTcXnhCS/WQvvdbHEIPhA2ICtuugU18KDNkovDr4xWj pb1Vq9LUPw2K+WR7DWl0ODYz0F63QcgpA8rBbK98= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730598AbfLSSzA (ORCPT ); Thu, 19 Dec 2019 13:55:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:50656 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730596AbfLSSzA (ORCPT ); Thu, 19 Dec 2019 13:55:00 -0500 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 75CC7206EC; Thu, 19 Dec 2019 18:54:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576781699; bh=Be1O2j7Z4b1WMstvecL4tEM81NqtYVosdwqztphEMZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vVbXIRG8GiS//HAnTBrW5aPAgYCLejA/4kB0AYlDrtiij+zknKS1gA1IbgpW4i3Fc fV/YEx9WGsarhX+ays+d6CEQ8+bKFyF1peJ1tm0GJ0rUKH4ljnmJdhmJrbne+YrLMN /pmRqUeTfbdCcQVD7DGoNBYSTZsYvnGSoCFqMNx4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Boris Brezillon , Steven Price , Alyssa Rosenzweig , Rob Herring Subject: [PATCH 5.4 45/80] drm/panfrost: Fix a race in panfrost_gem_free_object() Date: Thu, 19 Dec 2019 19:34:37 +0100 Message-Id: <20191219183113.201635558@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191219183031.278083125@linuxfoundation.org> References: <20191219183031.278083125@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: Boris Brezillon commit aed44cbeae2b7674cd155ba5cc6506aafe46a94e upstream. panfrost_gem_shrinker_scan() might purge a BO (release the sgt and kill the GPU mapping) that's being freed by panfrost_gem_free_object() if we don't remove the BO from the shrinker list at the beginning of panfrost_gem_free_object(). Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support") Cc: Signed-off-by: Boris Brezillon Reviewed-by: Steven Price Acked-by: Alyssa Rosenzweig Signed-off-by: Rob Herring Link: https://patchwork.freedesktop.org/patch/msgid/20191129135908.2439529-5-boris.brezillon@collabora.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/panfrost/panfrost_gem.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -19,6 +19,16 @@ static void panfrost_gem_free_object(str struct panfrost_gem_object *bo = to_panfrost_bo(obj); struct panfrost_device *pfdev = obj->dev->dev_private; + /* + * Make sure the BO is no longer inserted in the shrinker list before + * taking care of the destruction itself. If we don't do that we have a + * race condition between this function and what's done in + * panfrost_gem_shrinker_scan(). + */ + mutex_lock(&pfdev->shrinker_lock); + list_del_init(&bo->base.madv_list); + mutex_unlock(&pfdev->shrinker_lock); + if (bo->sgts) { int i; int n_sgt = bo->base.base.size / SZ_2M; @@ -33,11 +43,6 @@ static void panfrost_gem_free_object(str kfree(bo->sgts); } - mutex_lock(&pfdev->shrinker_lock); - if (!list_empty(&bo->base.madv_list)) - list_del(&bo->base.madv_list); - mutex_unlock(&pfdev->shrinker_lock); - drm_gem_shmem_free_object(obj); }