Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754679AbdLGNzR (ORCPT ); Thu, 7 Dec 2017 08:55:17 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:33016 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753815AbdLGNBX (ORCPT ); Thu, 7 Dec 2017 08:01:23 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chris Wilson , Sumit Semwal , Sean Paul , Gustavo Padovan , Gustavo Padovan , Jisheng Zhang Subject: [PATCH 4.9 093/109] dma-buf/sw-sync: Fix locking around sync_timeline lists Date: Thu, 7 Dec 2017 13:57:17 +0100 Message-Id: <20171207125645.389569471@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171207125634.631485452@linuxfoundation.org> References: <20171207125634.631485452@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6221 Lines: 204 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Wilson commit d3862e44daa7a0c94d2f6193502a8c49379acfce upstream. The sync_pt were not adding themselves atomically to the timeline lists, corruption imminent. Only a single list is required to track the unsignaled sync_pt, so reduce it and rename the lock more appropriately along with using idiomatic names to distinguish a list from links along it. v2: Prevent spinlock recursion on free during create (next patch) and fixup crossref in kerneldoc Signed-off-by: Chris Wilson Cc: Sumit Semwal Cc: Sean Paul Cc: Gustavo Padovan Reviewed-by: Sean Paul Signed-off-by: Gustavo Padovan Link: http://patchwork.freedesktop.org/patch/msgid/20170629210532.5617-1-chris@chris-wilson.co.uk [s/dma_fence/fence/g - gregkh] Cc: Jisheng Zhang Signed-off-by: Greg Kroah-Hartman --- drivers/dma-buf/sw_sync.c | 48 +++++++++++++++++-------------------------- drivers/dma-buf/sync_debug.c | 9 +++----- drivers/dma-buf/sync_debug.h | 22 +++++++------------ 3 files changed, 31 insertions(+), 48 deletions(-) --- a/drivers/dma-buf/sw_sync.c +++ b/drivers/dma-buf/sw_sync.c @@ -96,9 +96,8 @@ struct sync_timeline *sync_timeline_crea obj->context = fence_context_alloc(1); strlcpy(obj->name, name, sizeof(obj->name)); - INIT_LIST_HEAD(&obj->child_list_head); - INIT_LIST_HEAD(&obj->active_list_head); - spin_lock_init(&obj->child_list_lock); + INIT_LIST_HEAD(&obj->pt_list); + spin_lock_init(&obj->lock); sync_timeline_debug_add(obj); @@ -139,17 +138,15 @@ static void sync_timeline_signal(struct trace_sync_timeline(obj); - spin_lock_irq(&obj->child_list_lock); + spin_lock_irq(&obj->lock); obj->value += inc; - list_for_each_entry_safe(pt, next, &obj->active_list_head, - active_list) { + list_for_each_entry_safe(pt, next, &obj->pt_list, link) if (fence_is_signaled_locked(&pt->base)) - list_del_init(&pt->active_list); - } + list_del_init(&pt->link); - spin_unlock_irq(&obj->child_list_lock); + spin_unlock_irq(&obj->lock); } /** @@ -171,15 +168,15 @@ static struct sync_pt *sync_pt_create(st if (!pt) return NULL; - spin_lock_irq(&obj->child_list_lock); - sync_timeline_get(obj); - fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock, + fence_init(&pt->base, &timeline_fence_ops, &obj->lock, obj->context, value); - list_add_tail(&pt->child_list, &obj->child_list_head); - INIT_LIST_HEAD(&pt->active_list); + INIT_LIST_HEAD(&pt->link); - spin_unlock_irq(&obj->child_list_lock); + spin_lock_irq(&obj->lock); + if (!fence_is_signaled_locked(&pt->base)) + list_add_tail(&pt->link, &obj->pt_list); + spin_unlock_irq(&obj->lock); return pt; } @@ -200,15 +197,15 @@ static void timeline_fence_release(struc { struct sync_pt *pt = fence_to_sync_pt(fence); struct sync_timeline *parent = fence_parent(fence); - unsigned long flags; - spin_lock_irqsave(fence->lock, flags); + if (!list_empty(&pt->link)) { + unsigned long flags; - list_del(&pt->child_list); - if (!list_empty(&pt->active_list)) - list_del(&pt->active_list); - - spin_unlock_irqrestore(fence->lock, flags); + spin_lock_irqsave(fence->lock, flags); + if (!list_empty(&pt->link)) + list_del(&pt->link); + spin_unlock_irqrestore(fence->lock, flags); + } sync_timeline_put(parent); fence_free(fence); @@ -223,13 +220,6 @@ static bool timeline_fence_signaled(stru static bool timeline_fence_enable_signaling(struct fence *fence) { - struct sync_pt *pt = fence_to_sync_pt(fence); - struct sync_timeline *parent = fence_parent(fence); - - if (timeline_fence_signaled(fence)) - return false; - - list_add_tail(&pt->active_list, &parent->active_list_head); return true; } --- a/drivers/dma-buf/sync_debug.c +++ b/drivers/dma-buf/sync_debug.c @@ -119,13 +119,12 @@ static void sync_print_obj(struct seq_fi seq_printf(s, "%s: %d\n", obj->name, obj->value); - spin_lock_irq(&obj->child_list_lock); - list_for_each(pos, &obj->child_list_head) { - struct sync_pt *pt = - container_of(pos, struct sync_pt, child_list); + spin_lock_irq(&obj->lock); + list_for_each(pos, &obj->pt_list) { + struct sync_pt *pt = container_of(pos, struct sync_pt, link); sync_print_fence(s, &pt->base, false); } - spin_unlock_irq(&obj->child_list_lock); + spin_unlock_irq(&obj->lock); } static void sync_print_sync_file(struct seq_file *s, --- a/drivers/dma-buf/sync_debug.h +++ b/drivers/dma-buf/sync_debug.h @@ -24,43 +24,37 @@ * struct sync_timeline - sync object * @kref: reference count on fence. * @name: name of the sync_timeline. Useful for debugging - * @child_list_head: list of children sync_pts for this sync_timeline - * @child_list_lock: lock protecting @child_list_head and fence.status - * @active_list_head: list of active (unsignaled/errored) sync_pts + * @lock: lock protecting @pt_list and @value + * @pt_list: list of active (unsignaled/errored) sync_pts * @sync_timeline_list: membership in global sync_timeline_list */ struct sync_timeline { struct kref kref; char name[32]; - /* protected by child_list_lock */ + /* protected by lock */ u64 context; int value; - struct list_head child_list_head; - spinlock_t child_list_lock; - - struct list_head active_list_head; + struct list_head pt_list; + spinlock_t lock; struct list_head sync_timeline_list; }; static inline struct sync_timeline *fence_parent(struct fence *fence) { - return container_of(fence->lock, struct sync_timeline, - child_list_lock); + return container_of(fence->lock, struct sync_timeline, lock); } /** * struct sync_pt - sync_pt object * @base: base fence object - * @child_list: sync timeline child's list - * @active_list: sync timeline active child's list + * @link: link on the sync timeline's list */ struct sync_pt { struct fence base; - struct list_head child_list; - struct list_head active_list; + struct list_head link; }; #ifdef CONFIG_SW_SYNC