linux-kernel - Re: 3.14-mw regression: rtl8169 WARNING: DMA-API: exceeded 7 overlapping mappings of pfn 55ebe

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Date:	Fri, 7 Feb 2014 11:21:28 +0100
From:	Sander Eikelenboom <linux@...elenboom.it>
To:	Dan Williams <dan.j.williams@...el.com>
CC:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Wei Liu <wei.liu2@...rix.com>,
	Francois Romieu <romieu@...zoreil.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: 3.14-mw regression: rtl8169 WARNING: DMA-API: exceeded 7 overlapping mappings of pfn 55ebe


Thursday, February 6, 2014, 8:12:15 PM, you wrote:

> On Thu, Feb 6, 2014 at 6:27 AM, Sander Eikelenboom <linux@...elenboom.it> wrote:
>>>>> Not using it seems to prevent the warning, but before 3.14 i have never seen this (with r8169.use_dac=1)
>>
>>> If you are still hitting this with the patch:
>>
>>>   59f2e7df574c dma-debug: fix overlap detection
>>
>>> ...then I'm more inclined to think it is an actual positive report.
>>
>>> If you don't mind I'll send some debug patches to narrow this down.
>>
>> Please do .. sounds better than bisecting :-)
>>

> Hi, attached is a patch that should give some insight whether the
> driver is triggering many overlapping mappings.  Try it on top of
> 3.14-rc1.

> Thank you for the debug help!

Hi Dan,

Nifty feature the trace_printk .. however is there a way to limit the list it's spitting out
to what you are interesting in ?

At present the machine chokes while trying to spit out everything in one go and:
- it probably not of all of it is logged to disk because of all the rcu stalls and other problems it causes.
- the list on console at least looked a lot longer (and in the logs i don't see the original warn_on which should
  be just before the dump.

However .. attached is what i have got ...

--
Sander



View attachment "overlap_log.txt" of type "text/plain" (335701 bytes)