From: Peter Korsgaard <jacmet-OfajU3CKLf1/SzgSGea1oA@public.gmane.org>
To: Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org>
Cc: jeff-o2qLIJkoznsdnm+yROfE0A@public.gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH RESEND] dm9601: don't do usb transfers of data on stack
Date: Fri, 11 Jul 2008 14:17:58 +0200 [thread overview]
Message-ID: <87vdzcehs9.fsf@macbook.be.48ers.dk> (raw)
In-Reply-To: <200807111400.38312.oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org> (Oliver Neukum's message of "Fri\, 11 Jul 2008 14\:00\:37 +0200")
>>>>> "Oliver" == Oliver Neukum <oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org> writes:
>> dm_{read,write}_shared_word() were doing USB transfers of data on stack,
>> which isn't allowed. Fix it by using the usbnet->data area like in
>> dm9601_set_multicast().
Oliver> You cannot do this. You've identified the bug correctly, but
Oliver> the fix is incorrect. Doing DMA on non coherent architectures
Oliver> means that any cacheline the buffer shares must not be
Oliver> touched while DMA may be running. If you embed the buffer
Oliver> into struct usbnet, how could you meet the guarantee?
Ahh. So kmalloc() / kfree() around the usb_control_msg isn dm_read /
dm_write is the way to go?
--
Bye, Peter Korsgaard
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next prev parent reply other threads:[~2008-07-11 12:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-11 11:37 [PATCH RESEND] dm9601: don't do usb transfers of data on stack Peter Korsgaard
[not found] ` <87mykoircs.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org>
2008-07-11 12:00 ` Oliver Neukum
[not found] ` <200807111400.38312.oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org>
2008-07-11 12:17 ` Peter Korsgaard [this message]
2008-07-11 12:22 ` Oliver Neukum
[not found] ` <200807111422.56406.oliver-GvhC2dPhHPQdnm+yROfE0A@public.gmane.org>
2008-07-11 12:55 ` Peter Korsgaard
2008-07-11 12:57 ` Peter Korsgaard
[not found] ` <87mykoefy4.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org>
2008-07-11 22:02 ` David Brownell
[not found] ` <200807111502.20507.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-07-14 7:07 ` Peter Korsgaard
[not found] ` <87wsjp9c5n.fsf-uXGAPMMVk8amE9MCos8gUmSdvHPH+/yF@public.gmane.org>
2008-07-30 8:48 ` Jeff Garzik
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