linux-kernel - Re: drivers/mmc/card/block.c infinite loop in mmc_blk_err_check waiting on R1_READY_FOR

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Message-ID: <87k3u6id1j.fsf@octavius.laptop.org>
Date:	Wed, 31 Oct 2012 16:47:52 -0400
From:	Chris Ball <cjb@...top.org>
To:	Trey Ramsay <tramsay@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org, linux-mmc@...r.kernel.org,
	Rich Rattanni <rattanni@...il.com>,
	Radovan Lekanovic <lekanovic@...il.com>
Subject: Re: drivers/mmc/card/block.c infinite loop in mmc_blk_err_check waiting on R1_READY_FOR_DATA

Hi,

On Wed, Oct 31 2012, Trey Ramsay wrote:
> In the 3.7-rc3 kernel, there is an infinite loop in the
> mmc_blk_err_check() function in drivers/mmc/card/block.c that can be
> caused bad hardware. This loop has moved around a little, but appears
> to have been around in the kernel since v2.6.12.  The code will loop
> forever on write if the card isn't ready for data or if it's in
> program mode.  I did some searching and saw that it was reported to
> linux-mmc@...r.kernel.org
> http://permalink.gmane.org/gmane.linux.kernel.mmc/2021 back in May but
> didn't see a response.  Should there be a maximum retry count or a
> timeout to prevent an infinite loop?

Yes, a (long) timeout is a good idea, and there are three different
places where we use this type of loop waiting for R1_STATE_PRG to drop.
I'll add this to my TODO list, but feel free to fix it if you want to.

Thanks,

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