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 for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20090616151628V.fujita.tomonori@lab.ntt.co.jp>
Date:	Tue, 16 Jun 2009 15:16:37 +0900
From:	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
To:	joerg.roedel@....com
Cc:	stefanr@...6.in-berlin.de, ben-linux@...ff.org,
	linux-kernel@...r.kernel.org
Subject: Re: dma-debug: check_for_stack background?

On Mon, 15 Jun 2009 10:13:55 +0200
Joerg Roedel <joerg.roedel@....com> wrote:

> On Sun, Jun 14, 2009 at 11:43:42PM +0200, Stefan Richter wrote:
> > Ben Dooks wrote:
> >> On Sun, Jun 14, 2009 at 08:56:29PM +0200, Stefan Richter wrote:
> >>> the DMA debug facility warns  about mappings of on-stack memory.  
> >>> What's the problem with that?
> > ...
> >> I'm not sure if it is possible on all architectures, however the
> >> DMA mapping documentation prohibts the use of stack memory.
> >
> > Ah, it has all been documented in plain sight for ages.  Thanks for the  
> > pointer.
> 
> Problem is that the stack might go away or could be otherwise reused
> while the DMA is in-flight. This could cause really hard to debug
> problems.

Not true. Even if you use the stack buffer for DMA synchronously, it
doesn't work (we had the bad code like starting dma and waiting for
the completion).

On some architectures, we can't use the stack buffer for DMA. That's
why the DMA mapping documentation prohibits the use of stack memory
for DMA.
--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ