From: David Miller <davem@davemloft.net>
To: arnd@arndb.de
Cc: ceggers@gmx.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH] usb/mcs7830: Don't use buffers from stack for USB transfers
Date: Tue, 20 Jan 2009 14:47:19 -0800 (PST) [thread overview]
Message-ID: <20090120.144719.120709836.davem@davemloft.net> (raw)
In-Reply-To: <200901202345.47792.arnd@arndb.de>
From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 20 Jan 2009 23:45:47 +0100
> On Tuesday 20 January 2009, you wrote:
> > From: Christian Eggers <christian.eggers@kathrein.de>
> >
> > mcs7830_set_reg() and mcs7830_get_reg() are called with buffers
> > from stack which must not be used directly for USB transfers.
> > This causes corruption of the stack particulary on non x86
> > architectures because DMA may be used for these transfers.
> >
> > Signed-off-by: Christian Eggers <christian.eggers@kathrein.de>
>
> Have you observed problems with this, or just suspected trouble?
Yes, this is in response to SH platform failures.
You cannot DMA from/to the kernel stack, because it might not be in
the aliased linear mapping of physical memory. It could even be
vmalloc()'d memory on some platforms.
next prev parent reply other threads:[~2009-01-20 22:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-20 20:29 [PATCH] usb/mcs7830: Don't use buffers from stack for USB transfers Christian Eggers
2009-01-20 20:32 ` David Miller
2009-01-20 22:45 ` Arnd Bergmann
2009-01-20 22:47 ` David Miller [this message]
2009-01-20 23:17 ` Arnd Bergmann
2009-01-20 23:23 ` David Miller
2009-01-20 23:36 ` Oliver Neukum
2009-01-20 23:37 ` Arnd Bergmann
2009-01-20 23:39 ` David Miller
2009-01-20 23:28 ` Oliver Neukum
2009-01-20 22:50 ` Oliver Neukum
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