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From: Chris Ball <cjb@laptop.org>
To: Aaron Lu <aaron.lu@amd.com>
Cc: Girish K S <girish.shivananjappa@linaro.org>,
	Subhash Jadavani <subhashj@codeaurora.org>,
	Philip Rakity <prakity@marvell.com>,
	linux-mmc@vger.kernel.org, Aaron Lu <aaron.lwe@gmail.com>
Subject: Re: [PATCH v2] mmc: sdhci: fix incorrect command used in tuning
Date: Thu, 08 Nov 2012 20:46:54 -0500	[thread overview]
Message-ID: <87zk2reeep.fsf@octavius.laptop.org> (raw)
In-Reply-To: <87wqxzal6b.fsf@octavius.laptop.org> (Chris Ball's message of "Mon, 05 Nov 2012 14:45:16 -0500")

Hi Aaron,

On Mon, Nov 05 2012, Chris Ball wrote:
> On Tue, Jul 03 2012, Aaron Lu wrote:
>>  		 */
>>  		if ((host->flags & SDHCI_NEEDS_RETUNING) &&
>>  		    !(present_state & (SDHCI_DOING_WRITE | SDHCI_DOING_READ))) {
>> +			/* eMMC uses cmd21 while sd and sdio use cmd19 */
>> +			tuning_opcode = mmc->card->type == MMC_TYPE_MMC ?
>> +				MMC_SEND_TUNING_BLOCK_HS200 :
>> +				MMC_SEND_TUNING_BLOCK;
>
> This is causing a NULL deref crash here when run on host controllers
> with no card inserted -- mmc->card is NULL, as you'd expect, yet it's
> dereferenced anyway.  Maybe the system you tested it on only has an
> eMMC, so you never noticed that it crashes if there's no card present?
> Or maybe it's abnormal for host controllers to set SDHCI_NEEDS_RETUNING
> when there's no card present?

I'm going to send my fix to Linus (and hence stable@) tomorrow morning,
since it's important to remove this crash.  Let me know what you think
when you get a chance.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

      reply	other threads:[~2012-11-09  1:47 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-03  9:27 [PATCH v2] mmc: sdhci: fix incorrect command used in tuning Aaron Lu
2012-07-03  9:58 ` Girish K S
2012-07-03 11:31   ` Aaron Lu
2012-07-03 11:57     ` Girish K S
2012-07-03 12:00       ` Girish K S
2012-07-03 12:02       ` Girish K S
2012-07-03 13:52         ` Aaron Lu
2012-07-03 14:03 ` Philip Rakity
2012-07-04  0:37 ` Chris Ball
2012-07-04  5:11   ` Aaron Lu
2012-11-05 19:45 ` Chris Ball
2012-11-09  1:46   ` Chris Ball [this message]

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