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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no 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 7E3D0C34047 for ; Wed, 19 Feb 2020 09:27:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A69224656 for ; Wed, 19 Feb 2020 09:27:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582104476; bh=9kyEssX5GEbwlVExA9JUPsMK72bF0lQACS2bjDvlqvE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=EbS0WWU7jPWAobhZ30mK5sOJySJxw4wYrYJ7FpUjrEMFPNMDgdqXeKb9dwxqcamTK tJ0NbHkZXoXN4epsFtOZDD2o7jaOqOJ+IhUjK01yOuce3ksNY0vkrvTdkeajslvq8b /BINVd0ZAPUCjJBEvhoqdtmfennL9cxN3MGB05Yo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726270AbgBSJ14 (ORCPT ); Wed, 19 Feb 2020 04:27:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:52758 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726195AbgBSJ1z (ORCPT ); Wed, 19 Feb 2020 04:27:55 -0500 Received: from localhost (unknown [106.201.32.165]) (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 849AA2064C; Wed, 19 Feb 2020 09:27:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582104475; bh=9kyEssX5GEbwlVExA9JUPsMK72bF0lQACS2bjDvlqvE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ps8pNHJpu5H+1dtWXtP1nZ/vMn+PISHycpZFQKHsacq25au3EysOMbcLKDHH3BAd2 y73T6NuhAIbWZ8PVVOg4Zm8zeE8VZvgaMlmRXAXSZpaYiONEGAhq11oUnKgpObKaGa nfYJZdekeW4qPjWgALR9BhLDf5iJ6mdLxnWo5SC4= Date: Wed, 19 Feb 2020 14:57:51 +0530 From: Vinod Koul To: Geert Uytterhoeven Cc: Linus Walleij , Dan Carpenter , kernel-janitors@vger.kernel.org, Jia-Ju Bai , dmaengine , Dan Williams , Linux ARM Subject: Re: [PATCH] dmaengine: coh901318: Fix a double lock bug in dma_tc_handle() Message-ID: <20200219092751.GH2618@vkoul-mobl> References: <20200217144050.3i4ymbytogod4ijn@kili.mountain> <20200219091754.GE2618@vkoul-mobl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 19-02-20, 10:20, Geert Uytterhoeven wrote: > Hi Vinod, > > On Wed, Feb 19, 2020 at 10:18 AM Vinod Koul wrote: > > On 17-02-20, 23:24, Geert Uytterhoeven wrote: > > > On Mon, Feb 17, 2020 at 3:41 PM Dan Carpenter wrote: > > > > The caller is already holding the lock so this will deadlock. > > > > > > > > Fixes: 0b58828c923e ("DMAENGINE: COH 901 318 remove irq counting") > > > > Signed-off-by: Dan Carpenter > > > > --- > > > > This is the second double lock bug found using static analysis. The > > > > previous one was commit 627469e4445b ("dmaengine: coh901318: Fix a > > > > double-lock bug"). > > > > > > > > The fact that this has been broken for ten years suggests that no one > > > > has the hardware. > > > > > > Or this only runs CONFIG_SMP=n kernels? > > > This seems to be used in arch/arm/boot/dts/ste-u300.dts only, and > > > CONFIG_ARCH_U300 is a ARCH_MULTI_V5 platform, which looks like > > > it doesn't support SMP? > > > > Should we drop the driver then..? > > Why? Because spinlocks are no-ops on SMP=n, and spinlock bugs thus don't > affect the single platform using the driver? That doesn't answer the question if anyone has a hardware and we have users :) Sorry I should have written better about hardware and testing rather than cryptic reply which may have suggested about SMP :) -- ~Vinod