From: Joerg Roedel <joerg.roedel@amd.com>
To: monstr@monstr.eu, linux-kernel@vger.kernel.org,
michal.simek@petalogix.com, arnd@arndb.de,
linux-arch@vger.kernel.org, fujita.tomonori@lab.ntt.co.jp,
akpm@linux-foundation.org, mingo@elte.hu
Subject: Re: Generic DMA - BUG_ON
Date: Wed, 20 Jan 2010 12:00:31 +0100 [thread overview]
Message-ID: <20100120110031.GD8665@amd.com> (raw)
In-Reply-To: <20100120105350.GA23394@flint.arm.linux.org.uk>
On Wed, Jan 20, 2010 at 10:53:50AM +0000, Russell King wrote:
> and ops is NULL, then this code will oops; you will get a full register
> dump and backtrace. You can use this information along with markup_oops.pl
> to find out where the problem is.
You can't rely on the oops if the code runs in process context. The
process may have address 0 mapped which would result in a security hole.
We had two of these bugs last year.
But I don't see any point in checking for dma_ops != NULL too. Any
developer would mention such a bug long before init is started.
Joerg
next prev parent reply other threads:[~2010-01-20 11:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-20 10:08 Generic DMA - BUG_ON monstr
2010-01-20 10:08 ` monstr
2010-01-20 10:08 ` [PATCH] asm-generic: dma: Add BUG_ON for uninitialized dma_ops monstr
2010-01-20 10:48 ` Alexey Dobriyan
2010-01-20 11:00 ` Geert Uytterhoeven
2010-01-20 10:56 ` Joerg Roedel
2010-01-22 1:11 ` FUJITA Tomonori
2010-01-20 10:53 ` Generic DMA - BUG_ON Russell King
2010-01-20 10:53 ` Russell King
2010-01-20 11:00 ` Joerg Roedel [this message]
2010-01-20 11:00 ` Joerg Roedel
2010-01-20 11:18 ` Michal Simek
2010-01-20 19:03 ` Arnd Bergmann
2010-01-21 15:51 ` Steven J. Magnani
2010-01-21 17:53 ` Russell King
2010-01-21 17:53 ` Russell King
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100120110031.GD8665@amd.com \
--to=joerg.roedel@amd.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=fujita.tomonori@lab.ntt.co.jp \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=michal.simek@petalogix.com \
--cc=mingo@elte.hu \
--cc=monstr@monstr.eu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox