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From: Olav Haugan <ohaugan@codeaurora.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: ngupta@vflare.org, sjenning@linux.vnet.ibm.com,
	linux-kernel@vger.kernel.org, minchan@kernel.org,
	linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH] staging: zsmalloc: Ensure handle is never 0 on success
Date: Wed, 06 Nov 2013 16:00:02 -0800	[thread overview]
Message-ID: <527AD802.6020902@codeaurora.org> (raw)
In-Reply-To: <20131106015645.GA28769@kroah.com>

On 11/5/2013 5:56 PM, Greg KH wrote:
> On Tue, Nov 05, 2013 at 04:54:12PM -0800, Olav Haugan wrote:
>> zsmalloc encodes a handle using the page pfn and an object
>> index. On some hardware platforms the pfn could be 0 and this
>> causes the encoded handle to be 0 which is interpreted as an
>> allocation failure.
> 
> What platforms specifically have this issue?

Currently some of Qualcomm SoC's have physical memory that starts at
address 0x0 which causes this problem. I believe this could be a problem
on any platforms if memory is configured to be starting at physical
address 0x0 for these platforms.

>>
>> To prevent this false error we ensure that the encoded handle
>> will not be 0 when allocation succeeds.
>>
>> Change-Id: Ifff930dcf254915b497aec5cb36f152a5e5365d6
> 
> What is this?  What can anyone do with it?

This is an identifier used by "Gerrit Code Review" to track changes to
the same patch. I will remove it.

Olav Haugan

-- 
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

  parent reply	other threads:[~2013-11-07  0:00 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-06  0:54 [PATCH] staging: zsmalloc: Ensure handle is never 0 on success Olav Haugan
2013-11-06  1:17 ` David Cohen
2013-11-06 20:56   ` Nitin Gupta
2013-11-06 23:46     ` Olav Haugan
2013-11-06  1:56 ` Greg KH
2013-11-06 21:09   ` Nitin Gupta
2013-11-06 22:10     ` Greg KH
2013-11-06 23:46       ` Nitin Gupta
2013-11-07  3:05         ` Greg KH
2013-11-07  0:00   ` Olav Haugan [this message]
2013-11-07  3:06     ` Greg KH
2013-11-07 22:57       ` Olav Haugan

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