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From: Greg KH <greg@kroah.com>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Eric Valette <eric.valette@free.fr>,
	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
	"John W. Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-usb@vger.kernel.org, Hin-Tak Leung <hintak.leung@gmail.com>
Subject: Re: DMA debug trace pointing to rtl8187
Date: Sat, 9 May 2009 12:29:59 -0700	[thread overview]
Message-ID: <20090509192959.GA1842@kroah.com> (raw)
In-Reply-To: <4A05BD77.9020003@lwfinger.net>

On Sat, May 09, 2009 at 12:29:27PM -0500, Larry Finger wrote:
> I think there is a second problem that John's fix does not treat. Although the
> buffer is removed from the stack, there is no assurance that the buffer obtained
> with kmalloc() is reachable by DMA. This case will be triggered if the USB
> adapter does 32-bit DMA and the system has more than 4 GB RAM.

Memory returned by kmalloc will always be able to be DMAable.  If not,
we have lots of problems :)

thanks,

greg k-h

  parent reply	other threads:[~2009-05-09 19:33 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-03 15:36 DMA debug trace pointing to rtl8187 Eric Valette
2009-05-06  4:30 ` FUJITA Tomonori
2009-05-06  5:21   ` Greg KH
2009-05-06  6:35   ` Eric Valette
2009-05-06  6:45     ` Greg KH
2009-05-06 18:02       ` [RFT] rtl8187: use DMA-aware buffers with usb_control_msg John W. Linville
2009-05-08 23:20         ` Hin-Tak Leung
2009-05-09  9:38           ` Eric Valette
2009-05-09 13:57             ` Greg KH
2009-05-09 15:50               ` John W. Linville
2009-05-09 16:35                 ` Greg KH
2009-05-09 21:24                 ` Larry Finger
2009-05-11 13:20                   ` John W. Linville
2009-05-11 22:23                     ` Hin-Tak Leung
2009-05-11 22:23                       ` Hin-Tak Leung
2009-05-06 18:03       ` DMA debug trace pointing to rtl8187 John W. Linville
2009-05-09 17:29       ` Larry Finger
2009-05-09 17:46         ` Eric Valette
2009-05-09 19:22           ` Eric Valette
2009-05-09 19:29         ` Greg KH [this message]
2009-05-09 20:19           ` Michael Buesch

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