From: Jussi Kivilinna <jussi.kivilinna@iki.fi>
To: Petko Manolov <petkan@nucleusys.com>
Cc: netdev@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH] net/usb: rtl8150: allocate URB transfer_buffer and setup_packet separately
Date: Sat, 10 Aug 2013 10:38:19 +0300 [thread overview]
Message-ID: <5205EDEB.3010707@iki.fi> (raw)
In-Reply-To: <alpine.DEB.2.10.1308092149270.3114@fry.nucleusys.com>
On 09.08.2013 21:50, Petko Manolov wrote:
> On Thu, 8 Aug 2013, Jussi Kivilinna wrote:
>
>> On 08.08.2013 18:14, Petko Manolov wrote:
>>> On Wed, 7 Aug 2013, Jussi Kivilinna wrote:
>>>
>>>> rtl8150 allocates URB transfer_buffer and setup_packet as part of same
>>>> structure 'struct async_req'. This can cause same cacheline to be
>>>> DMA-mapped twice with same URB. This can lead to memory corruption on
>>>> some systems.
>>>
>>> I can see performance impact due to the double mapping. However, memory
>>> corruption seems a bit too much for sane cache and DMA controllers. Out
>>> of interest - which is the architecture that will potentially corrupt the
>>> memory.
>>
>> rtlwifi driver had similar structure to allocate both setup_packet and
>> transfer_buffer in single go (overlapping dma-mapping cachelines) and
>> this caused problems on ARM/sunxi. Problems means: memory corruptions at
>> random locations, device freezes and lock-ups.
>
> Broken controllers?..
>
At first I thought so too, but I discussed about this at linux-usb, and answer
was that driver which uses same (dma/-)cacheline for multiple buffers is buggy..
http://marc.info/?l=linux-usb&m=137130407121137&w=2 (at end)
http://marc.info/?l=linux-usb&m=137137080902265&w=2
http://marc.info/?l=linux-usb&m=137242422120782&w=2
-Jussi
prev parent reply other threads:[~2013-08-10 7:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-07 13:36 [PATCH] net/usb: rtl8150: allocate URB transfer_buffer and setup_packet separately Jussi Kivilinna
2013-08-08 15:14 ` Petko Manolov
[not found] ` <alpine.DEB.2.10.1308081809120.4258-WOI+tvYbpdBn9MRfDTB0XAC/G2K4zDHf@public.gmane.org>
2013-08-08 19:43 ` Jussi Kivilinna
2013-08-09 18:50 ` Petko Manolov
2013-08-10 7:38 ` Jussi Kivilinna [this message]
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