From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751284AbcGWGZD (ORCPT ); Sat, 23 Jul 2016 02:25:03 -0400 Received: from mail-lf0-f50.google.com ([209.85.215.50]:35820 "EHLO mail-lf0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750712AbcGWGY6 (ORCPT ); Sat, 23 Jul 2016 02:24:58 -0400 Subject: Re: [PATCH 1/3] net: ethernet: ti: cpdma: fix lockup in cpdma_ctlr_destroy() To: Grygorii Strashko , "David S. Miller" , netdev@vger.kernel.org, Mugunthan V N References: <20160722135847.20557-1-grygorii.strashko@ti.com> <20160722135847.20557-2-grygorii.strashko@ti.com> Cc: Sekhar Nori , linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org From: Ivan Khoronzhuk Message-ID: Date: Sat, 23 Jul 2016 09:24:55 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160722135847.20557-2-grygorii.strashko@ti.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22.07.16 16:58, Grygorii Strashko wrote: > Fix deadlock in cpdma_ctlr_destroy() which is triggered now on > cpsw module removal: > cpsw_remove() > - cpdma_ctlr_destroy() > - spin_lock_irqsave(&ctlr->lock, flags) > - cpdma_ctlr_stop() > - spin_lock_irqsave(&ctlr->lock, flags); <- deadlock > - cpdma_chan_destroy() > - spin_lock_irqsave(&ctlr->lock, flags); <- deadlock > > The issue has not been observed before because CPDMA channels have > been destroyed manually by CPSW until commit d941ebe88a41 ("net: > ethernet: ti: cpsw: use destroy ctlr to destroy channels") was merged. > > Signed-off-by: Grygorii Strashko > --- > drivers/net/ethernet/ti/davinci_cpdma.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c > index a68652a..89242e9 100644 > --- a/drivers/net/ethernet/ti/davinci_cpdma.c > +++ b/drivers/net/ethernet/ti/davinci_cpdma.c > @@ -436,7 +436,6 @@ int cpdma_ctlr_destroy(struct cpdma_ctlr *ctlr) > if (!ctlr) > return -EINVAL; > > - spin_lock_irqsave(&ctlr->lock, flags); Should ctlr->state be checked under lock? Seems like here should be used unlocked static versions of cpdma_ctlr_stop() and cpdma_chan_destroy() instead. > if (ctlr->state != CPDMA_STATE_IDLE) > cpdma_ctlr_stop(ctlr); > > @@ -444,7 +443,6 @@ int cpdma_ctlr_destroy(struct cpdma_ctlr *ctlr) > cpdma_chan_destroy(ctlr->channels[i]); > > cpdma_desc_pool_destroy(ctlr->pool); > - spin_unlock_irqrestore(&ctlr->lock, flags); > return ret; > } > EXPORT_SYMBOL_GPL(cpdma_ctlr_destroy); > -- Regards, Ivan Khoronzhuk