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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 9DADDC07E9E for ; Tue, 6 Jul 2021 11:16:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92CF661C58 for ; Tue, 6 Jul 2021 11:16:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232426AbhGFLSj (ORCPT ); Tue, 6 Jul 2021 07:18:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:53226 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232165AbhGFLRn (ORCPT ); Tue, 6 Jul 2021 07:17:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3E4B661C37; Tue, 6 Jul 2021 11:15:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625570104; bh=v2U3oFrCcd0K1eyC+/MWzXjy/77AblsNqWuQmzV9OOI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ruN/jJx35TgDIGCJKxEPYGvry1oqzICRi5PE8sOk/7X+T3q9psV2R63Ehbb/44gDg oVcYx30i2nsXYd6UaDbGW/cC8Ma32wX8sBzzLP6aD2+cqu5rRxx5SrMmJ7Z7VWB144 utfz+mnYlssQ8VF0Jo8VyIsxOT/xsccZx2hUrf4rwhw8gwDPxWvoSb929ErYisrQ3u Rz2KRppK2nkrNMbgUCViladzROdyoUdjJVpYce4VnchyousUlVmeWRkX4crl/bY0fp 7m5pquwX9yA0k2CgEpjen5wETf2FaGz8MnDL2T02pOeEmbzzFHS+OHoONucN22ApXo p1DChp46j/Wcw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrey Grodzovsky , =?UTF-8?q?Christian=20K=C3=B6nig?= , Sasha Levin , dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 5.13 038/189] drm/scheduler: Fix hang when sched_entity released Date: Tue, 6 Jul 2021 07:11:38 -0400 Message-Id: <20210706111409.2058071-38-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210706111409.2058071-1-sashal@kernel.org> References: <20210706111409.2058071-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andrey Grodzovsky [ Upstream commit c61cdbdbffc169dc7f1e6fe94dfffaf574fe672a ] Problem: If scheduler is already stopped by the time sched_entity is released and entity's job_queue not empty I encountred a hang in drm_sched_entity_flush. This is because drm_sched_entity_is_idle never becomes false. Fix: In drm_sched_fini detach all sched_entities from the scheduler's run queues. This will satisfy drm_sched_entity_is_idle. Also wakeup all those processes stuck in sched_entity flushing as the scheduler main thread which wakes them up is stopped by now. v2: Reverse order of drm_sched_rq_remove_entity and marking s_entity as stopped to prevent reinserion back to rq due to race. v3: Drop drm_sched_rq_remove_entity, only modify entity->stopped and check for it in drm_sched_entity_is_idle Signed-off-by: Andrey Grodzovsky Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20210512142648.666476-14-andrey.grodzovsky@amd.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/scheduler/sched_entity.c | 3 ++- drivers/gpu/drm/scheduler/sched_main.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index f0790e9471d1..cb58f692dad9 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -116,7 +116,8 @@ static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity) rmb(); /* for list_empty to work without lock */ if (list_empty(&entity->list) || - spsc_queue_count(&entity->job_queue) == 0) + spsc_queue_count(&entity->job_queue) == 0 || + entity->stopped) return true; return false; diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 92d8de24d0a1..c105c807d7e5 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -888,9 +888,33 @@ EXPORT_SYMBOL(drm_sched_init); */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { + struct drm_sched_entity *s_entity; + int i; + if (sched->thread) kthread_stop(sched->thread); + for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) { + struct drm_sched_rq *rq = &sched->sched_rq[i]; + + if (!rq) + continue; + + spin_lock(&rq->lock); + list_for_each_entry(s_entity, &rq->entities, list) + /* + * Prevents reinsertion and marks job_queue as idle, + * it will removed from rq in drm_sched_entity_fini + * eventually + */ + s_entity->stopped = true; + spin_unlock(&rq->lock); + + } + + /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */ + wake_up_all(&sched->job_scheduled); + /* Confirm no work left behind accessing device structures */ cancel_delayed_work_sync(&sched->work_tdr); -- 2.30.2