From patchwork Sun Nov 1 17:40:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Brezillon X-Patchwork-Id: 317327 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, 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 91B5AC388F9 for ; Sun, 1 Nov 2020 17:40:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 639A820853 for ; Sun, 1 Nov 2020 17:40:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727086AbgKARk0 (ORCPT ); Sun, 1 Nov 2020 12:40:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727024AbgKARk0 (ORCPT ); Sun, 1 Nov 2020 12:40:26 -0500 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3109FC0617A6 for ; Sun, 1 Nov 2020 09:40:25 -0800 (PST) Received: from localhost.localdomain (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 77F421F44AA4; Sun, 1 Nov 2020 17:40:22 +0000 (GMT) From: Boris Brezillon To: Rob Herring , Tomeu Vizoso , Alyssa Rosenzweig , Steven Price , Robin Murphy Cc: dri-devel@lists.freedesktop.org, Boris Brezillon , stable@vger.kernel.org, Christian Hewitt Subject: [PATCH] drm/panfrost: Fix a deadlock between the shrinker and madvise path Date: Sun, 1 Nov 2020 18:40:16 +0100 Message-Id: <20201101174016.839110-1-boris.brezillon@collabora.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org panfrost_ioctl_madvise() and panfrost_gem_purge() acquire the mappings and shmem locks in different orders, thus leading to a potential the mappings lock first. Fixes: bdefca2d8dc0 ("drm/panfrost: Add the panfrost_gem_mapping concept") Cc: Cc: Christian Hewitt Reported-by: Christian Hewitt Signed-off-by: Boris Brezillon --- drivers/gpu/drm/panfrost/panfrost_gem.c | 4 +--- drivers/gpu/drm/panfrost/panfrost_gem.h | 2 +- drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c | 14 +++++++++++--- 3 files changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c index cdf1a8754eba..0c0243eaee81 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c @@ -105,14 +105,12 @@ void panfrost_gem_mapping_put(struct panfrost_gem_mapping *mapping) kref_put(&mapping->refcount, panfrost_gem_mapping_release); } -void panfrost_gem_teardown_mappings(struct panfrost_gem_object *bo) +void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo) { struct panfrost_gem_mapping *mapping; - mutex_lock(&bo->mappings.lock); list_for_each_entry(mapping, &bo->mappings.list, node) panfrost_gem_teardown_mapping(mapping); - mutex_unlock(&bo->mappings.lock); } int panfrost_gem_open(struct drm_gem_object *obj, struct drm_file *file_priv) diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h index b3517ff9630c..8088d5fd8480 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem.h +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h @@ -82,7 +82,7 @@ struct panfrost_gem_mapping * panfrost_gem_mapping_get(struct panfrost_gem_object *bo, struct panfrost_file_priv *priv); void panfrost_gem_mapping_put(struct panfrost_gem_mapping *mapping); -void panfrost_gem_teardown_mappings(struct panfrost_gem_object *bo); +void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo); void panfrost_gem_shrinker_init(struct drm_device *dev); void panfrost_gem_shrinker_cleanup(struct drm_device *dev); diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c index 288e46c40673..1b9f68d8e9aa 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c @@ -40,18 +40,26 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj) { struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); struct panfrost_gem_object *bo = to_panfrost_bo(obj); + bool ret = false; if (atomic_read(&bo->gpu_usecount)) return false; - if (!mutex_trylock(&shmem->pages_lock)) + if (!mutex_trylock(&bo->mappings.lock)) return false; - panfrost_gem_teardown_mappings(bo); + if (!mutex_trylock(&shmem->pages_lock)) + goto unlock_mappings; + + panfrost_gem_teardown_mappings_locked(bo); drm_gem_shmem_purge_locked(obj); + ret = true; mutex_unlock(&shmem->pages_lock); - return true; + +unlock_mappings: + mutex_unlock(&bo->mappings.lock); + return ret; } static unsigned long