linux-kernel - Re: [PATCH] mmc: core: fix dead loop of mmc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <560BCF1B.7050302@intel.com>
Date:	Wed, 30 Sep 2015 15:01:31 +0300
From:	Adrian Hunter <adrian.hunter@...el.com>
To:	Chaotian Jing <chaotian.jing@...iatek.com>,
	Ulf Hansson <ulf.hansson@...aro.org>
Cc:	Matthias Brugger <matthias.bgg@...il.com>,
	Johan Rudholm <johan.rudholm@...s.com>,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	Shawn Lin <shawn.lin@...k-chips.com>,
	Andrew Gabbasov <andrew_gabbasov@...tor.com>,
	David Jander <david@...tonic.nl>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
	Sascha Hauer <kernel@...gutronix.de>
Subject: Re: [PATCH] mmc: core: fix dead loop of mmc_retune

On 30/09/15 12:37, Chaotian Jing wrote:
> When get a CRC error, start the mmc_retune, it will issue CMD19/CMD21
> to do tune, assume there were 10 clock phase need to try, phase 0 to
> phase 6 is ok, phase 7 to phase 9 is NG, we try it from 0 to 9, so
> the last CMD19/CMD21 will get CRC error, host->need_retune was set and
> cause mmc_retune was called, then dead loop of mmc_retune
> 
> Signed-off-by: Chaotian Jing <chaotian.jing@...iatek.com>

Wasn't my idea to have this CRC checking in the core ;-) and sdhci
doesn't put it's tuning commands through a mmc request so it doesn't
see this issue.

But definitely the CRC logic is not meant for the tuning commands, so

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

> ---
>  drivers/mmc/core/core.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 0520064..a3eb20b 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -134,9 +134,11 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
>  	int err = cmd->error;
>  
>  	/* Flag re-tuning needed on CRC errors */
> -	if (err == -EILSEQ || (mrq->sbc && mrq->sbc->error == -EILSEQ) ||
> +	if ((cmd->opcode != MMC_SEND_TUNING_BLOCK &&
> +	    cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200) &&
> +	    (err == -EILSEQ || (mrq->sbc && mrq->sbc->error == -EILSEQ) ||
>  	    (mrq->data && mrq->data->error == -EILSEQ) ||
> -	    (mrq->stop && mrq->stop->error == -EILSEQ))
> +	    (mrq->stop && mrq->stop->error == -EILSEQ)))
>  		mmc_retune_needed(host);
>  
>  	if (err && cmd->retries && mmc_host_is_spi(host)) {
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/