Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752890AbdFLRIS (ORCPT ); Mon, 12 Jun 2017 13:08:18 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40548 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753778AbdFLPcD (ORCPT ); Mon, 12 Jun 2017 11:32:03 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Skeggs Subject: [PATCH 4.11 133/150] drm/nouveau/tmr: fully separate alarm execution/pending lists Date: Mon, 12 Jun 2017 17:25:40 +0200 Message-Id: <20170612152525.560685669@linuxfoundation.org> X-Mailer: git-send-email 2.13.1 In-Reply-To: <20170612152519.404936272@linuxfoundation.org> References: <20170612152519.404936272@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: 1912 Lines: 57 4.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Skeggs commit b4e382ca7586a63b6c1e5221ce0863ff867c2df6 upstream. Reusing the list_head for both is a bad idea. Callback execution is done with the lock dropped so that alarms can be rescheduled from the callback, which means that with some unfortunate timing, lists can get corrupted. The execution list should not require its own locking, the single function that uses it can only be called from a single context. Signed-off-by: Ben Skeggs Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/nouveau/include/nvkm/subdev/timer.h | 1 + drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c | 7 ++++--- 2 files changed, 5 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/nouveau/include/nvkm/subdev/timer.h +++ b/drivers/gpu/drm/nouveau/include/nvkm/subdev/timer.h @@ -4,6 +4,7 @@ struct nvkm_alarm { struct list_head head; + struct list_head exec; u64 timestamp; void (*func)(struct nvkm_alarm *); }; --- a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c @@ -50,7 +50,8 @@ nvkm_timer_alarm_trigger(struct nvkm_tim /* Move to completed list. We'll drop the lock before * executing the callback so it can reschedule itself. */ - list_move_tail(&alarm->head, &exec); + list_del_init(&alarm->head); + list_add(&alarm->exec, &exec); } /* Shut down interrupt if no more pending alarms. */ @@ -59,8 +60,8 @@ nvkm_timer_alarm_trigger(struct nvkm_tim spin_unlock_irqrestore(&tmr->lock, flags); /* Execute completed callbacks. */ - list_for_each_entry_safe(alarm, atemp, &exec, head) { - list_del_init(&alarm->head); + list_for_each_entry_safe(alarm, atemp, &exec, exec) { + list_del(&alarm->exec); alarm->func(alarm); } }