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 21B3CC3A5A9 for ; Mon, 4 May 2020 18:07:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE18120721 for ; Mon, 4 May 2020 18:07:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615675; bh=bJ2l/CHYhXqqCQmXxTph5G9oI6DoxV3kjVdO3Qi3s38=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=IJbSaIMUOz51LT7U3sXf8TnuxQDQq8PvvOhsAeK6a2SLUgfXks8AKIyghLP5aMFy9 F9SWupG7i4BVpI8kFzHI5s810sIngCnOanlj8VsSVJAAJJ2GgNbZl/gc/hicAQusfY +IHdJM3Og8OxVcWHsr3KfwUt5pYJ+BaLWE8lAdM4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731308AbgEDSHq (ORCPT ); Mon, 4 May 2020 14:07:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:38678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732176AbgEDSHm (ORCPT ); Mon, 4 May 2020 14:07:42 -0400 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 278F320721; Mon, 4 May 2020 18:07:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615661; bh=bJ2l/CHYhXqqCQmXxTph5G9oI6DoxV3kjVdO3Qi3s38=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H9Cq5BuTeyKKghy+aCMQBB3+JBNn2GYhUZsOsolf29jWS0pdWH0io7nRtUiskmeRD 6UxEcmPo0c2ug3+6a4yDvh3tMXqeVks2S1tlMSTpUPL8dasD9jV9yE/7IlB8xI8gjI doByrODGPO6/hil2Ma/aHtRyPEo0EJ+iOWzhXOhs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Seraj Alijan , Andy Shevchenko , Vinod Koul Subject: [PATCH 5.6 71/73] dmaengine: dmatest: Fix process hang when reading wait parameter Date: Mon, 4 May 2020 19:58:14 +0200 Message-Id: <20200504165510.510085799@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200504165501.781878940@linuxfoundation.org> References: <20200504165501.781878940@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Shevchenko commit aa72f1d20ee973d68f26d46fce5e1cf6f9b7e1ca upstream. If we do % echo 1 > /sys/module/dmatest/parameters/run [ 115.851124] dmatest: Could not start test, no channels configured % echo dma8chan7 > /sys/module/dmatest/parameters/channel [ 127.563872] dmatest: Added 1 threads using dma8chan7 % cat /sys/module/dmatest/parameters/wait ... !!! HANG !!! ... The culprit is the commit 6138f967bccc ("dmaengine: dmatest: Use fixed point div to calculate iops") which makes threads not to run, but pending and being kicked off by writing to the 'run' node. However, it forgot to consider 'wait' routine to avoid above mentioned case. In order to fix this, check for really running threads, i.e. with pending and done flags unset. It's pity the culprit commit hadn't updated documentation and tested all possible scenarios. Fixes: 6138f967bccc ("dmaengine: dmatest: Use fixed point div to calculate iops") Cc: Seraj Alijan Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200428113518.70620-1-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/dmatest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/dma/dmatest.c +++ b/drivers/dma/dmatest.c @@ -240,7 +240,7 @@ static bool is_threaded_test_run(struct struct dmatest_thread *thread; list_for_each_entry(thread, &dtc->threads, node) { - if (!thread->done) + if (!thread->done && !thread->pending) return true; } }