linux-kernel - Re: [PATCH 2/2] staging: comedi: drivers: usbduxfast.c: fix for DMA buffers on stack

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 23 Feb 2013 20:34:42 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	walter harms <wharms@....de>
Cc:	Greg KH <gregkh@...uxfoundation.org>,
	Kumar Amit Mehta <gmate.amit@...il.com>,
	devel@...verdev.osuosl.org, kernel-janitors@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] staging: comedi: drivers: usbduxfast.c: fix for DMA
 buffers on stack

On Sat, Feb 23, 2013 at 04:59:43PM +0100, walter harms wrote:
> >> or is it possible to pass one byte
> >> in a register ? (aka char/int) without allocating ?
> > 
> > Nope, the USB host controllers must be able to DMA to this memory
> > location, so you have to allocate it dynamically, sorry.
> > 
> > thanks,
> 
> thx for clarification.
> 
> @Kumar Amit Mehta:
> Would you mind to add this as comment ? Allocating one byte does not
> look clever so maybe will come up with the idea of changing that.
> 

That can't happen.  The reason is already recorded in the git
history.  Greg and Ian know that DMA to stack memory doesn't work.
Most maintainers know about that.  If someone changed it back then
Fengguang would send an automatic email about it as soon as it was
committed to a public git tree.

regards,
dan carpenter
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/