From: Larry Finger <Larry.Finger@lwfinger.net>
To: Christian Lamparter <chunkeey@googlemail.com>
Cc: John W Linville <linville@tuxdriver.com>, linux-wireless@vger.kernel.org
Subject: Re: [PATCH V2] p54usb: Remove DMA buffer from stack
Date: Thu, 12 Nov 2009 10:27:43 -0600 [thread overview]
Message-ID: <4AFC377F.6050507@lwfinger.net> (raw)
In-Reply-To: <200911121051.11982.chunkeey@googlemail.com>
On 11/12/2009 03:51 AM, Christian Lamparter wrote:
> On Thursday 12 November 2009 01:02:29 Larry Finger wrote:
>> On 2.6.32-rc6 from wireless-testing, the following warning is emitted:
>>
>> ------------[ cut here ]------------
>> WARNING: at lib/dma-debug.c:860 check_for_stack+0xaa/0xe0()
>> Hardware name: HP Pavilion dv2700 Notebook PC
>> ehci_hcd 0000:00:02.1: DMA-API: device driver maps memory fromstack
>> [addr=ffff8800b6e2bca8]
-- snip --
>
> Acked-by: Christian Lamparter <chunkeey@googlemail.com>
>
> FYI, p54u_upload_firmware_net2280 will likely produce the same
> same WARN, since "__le32 reg;" is held on the stack as well.
I was pretty certain that the WARN is only for DMA buffers on the stack. After
reviewing the code lib/dma-debug.c, nothing changed my mind. In
p54u_upload_firmware_net2280, the buffer is kmalloc'ed already. It should be OK.
Larry
prev parent reply other threads:[~2009-11-12 16:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-12 0:02 [PATCH V2] p54usb: Remove DMA buffer from stack Larry Finger
2009-11-12 9:51 ` Christian Lamparter
2009-11-12 16:27 ` Larry Finger [this message]
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