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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 A5921C47247 for ; Thu, 7 May 2020 14:34:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C6E62073A for ; Thu, 7 May 2020 14:34:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588862088; bh=b1s7I7MQRORTqaB8/KOfE25r43ZKqozH8LCVeScbEHw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eJuS3R0Wg96RbKezMRyHGoUUtt1vTRJKlmrm9VXkiaBUht3M4PW305ZEb5nugSgtG 46CyX2uyro+GoohtLmnQcwxqBJr1I0OiieuXkHqL4Qmp8teurKvE+GFwxeL7EMKiKH AJuUf/fB+UKW6sGb9jK5QKtJEkEETknPhLczRzAk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728378AbgEGO3B (ORCPT ); Thu, 7 May 2020 10:29:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:56158 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728373AbgEGO3B (ORCPT ); Thu, 7 May 2020 10:29:01 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 445DE2073A; Thu, 7 May 2020 14:29:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588861741; bh=b1s7I7MQRORTqaB8/KOfE25r43ZKqozH8LCVeScbEHw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HQroLx8iIGosqP4QbF5JjfcCbhEEZVx10kczRygj8/hchZQIXZzosEyolhJPWxwMA BS1hXdfVGEatdYQWIsrJMhTOxB6+g2EyX+dnCnEJ2KPV/dBSqGeoSmTpvMHtY9AZi3 /CokNy90zCwJ3u1MP5s82oek6gBBqekWMfUwlBuk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andy Shevchenko , Seraj Alijan , Vinod Koul , Sasha Levin , dmaengine@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 24/35] dmaengine: dmatest: Fix process hang when reading 'wait' parameter Date: Thu, 7 May 2020 10:28:18 -0400 Message-Id: <20200507142830.26239-24-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200507142830.26239-1-sashal@kernel.org> References: <20200507142830.26239-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org From: Andy Shevchenko [ Upstream commit aa72f1d20ee973d68f26d46fce5e1cf6f9b7e1ca ] 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: Sasha Levin --- drivers/dma/dmatest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c index 4993e3e5c5b01..364dd34799d45 100644 --- a/drivers/dma/dmatest.c +++ b/drivers/dma/dmatest.c @@ -240,7 +240,7 @@ static bool is_threaded_test_run(struct dmatest_info *info) struct dmatest_thread *thread; list_for_each_entry(thread, &dtc->threads, node) { - if (!thread->done) + if (!thread->done && !thread->pending) return true; } } -- 2.20.1