From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757434Ab3KZWvO (ORCPT ); Tue, 26 Nov 2013 17:51:14 -0500 Received: from void.printf.net ([89.145.121.20]:57308 "EHLO void.printf.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751796Ab3KZWvL (ORCPT ); Tue, 26 Nov 2013 17:51:11 -0500 From: Chris Ball To: Chuansheng Liu Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, chuanxiao.dong@intel.com Subject: Re: [PATCH] mmc: sdhci: Setting the host->mrq to NULL before executing tuning References: <1383634365.26153.100.camel@cliu38-desktop-build> Date: Tue, 26 Nov 2013 17:50:59 -0500 In-Reply-To: <1383634365.26153.100.camel@cliu38-desktop-build> (Chuansheng Liu's message of "Tue, 05 Nov 2013 14:52:45 +0800") Message-ID: <87r4a2eq0c.fsf@octavius.laptop.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chuansheng, On Tue, Nov 05 2013, Chuansheng Liu wrote: > In function sdhci_request(), it is possible to do the tuning execution > like below: > > sdhci_request() { > spin_lock_irqsave(&host->lock, flags); > host->mrq = mrq; > ... > spin_unlock_irqrestore(&host->lock, flags); > > <=== Here it is possible one pending finish_tasklet get running > and it will operate the original mrq, and notified the mrq > is done, and causes memory corruption. > > sdhci_execute_tuning(mmc, tuning_opcode); > spin_lock_irqsave(&host->lock, flags); > host->mrq = mrq; > ... > } > > In the above race place, the original mrq should not be finished wrongly, > so here before unlock the spinlock, we need to set the host->mrq to NULL > to avoid this case. > > Signed-off-by: Liu, Chuansheng > --- > drivers/mmc/host/sdhci.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 7a7fb4f..c7a001a 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -1391,6 +1391,13 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq) > mmc->card->type == MMC_TYPE_MMC ? > MMC_SEND_TUNING_BLOCK_HS200 : > MMC_SEND_TUNING_BLOCK; > + > + /* Here we need to set the host->mrq to NULL, > + * in case the penging finish_tasklet > + * operates it wrongly. > + */ > + host->mrq = NULL; > + > spin_unlock_irqrestore(&host->lock, flags); > sdhci_execute_tuning(mmc, tuning_opcode); > spin_lock_irqsave(&host->lock, flags); Thanks, pushed to mmc-next for 3.14. - Chris. -- Chris Ball