From: Borislav Petkov <bp@alien8.de>
To: Dave Hansen <dave@sr71.net>
Cc: hpa@linux.intel.com, linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH 4/5] break up slow_virt_to_phys()
Date: Thu, 11 Apr 2013 19:12:46 +0200 [thread overview]
Message-ID: <20130411171246.GF27062@pd.tnic> (raw)
In-Reply-To: <5166E4CB.2060700@sr71.net>
On Thu, Apr 11, 2013 at 09:28:59AM -0700, Dave Hansen wrote:
> It's harsh for the cases where __pa()'s result never gets used
> directly, like for checking against 'high_memory'. If it gets used
> (like in /dev/mem's case) the kernel really is doing something it does
> not intend to do. It's essentially reading or writing garbage.
>
> On the other hand, I guess if we've been letting it do that bad thing
> for years, we might as well continue. We're not causing any _more_
> damage.
Well, if it wasn't an already used interface I'd say we forbid accesses
which are void of sense and issue a WARN_ON but who knows who'll come
screaming if we did that.
> I'm leaning toward making it a WARN_ON() at the moment. :)
Right, well, yeah, people would still be able to shoot themselves in the
foot over /dev/mem but now they'll at least be warned about it. Kernel's
job's done. :)
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2013-04-11 17:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-10 23:32 [PATCH 0/5] [RFC] rework /dev/mem code vs. highmem and DEBUG_VIRTUAL Dave Hansen
2013-04-10 23:32 ` [PATCH 1/5] clean up checks against "high_memory" variable Dave Hansen
2013-04-11 0:44 ` Borislav Petkov
2013-04-10 23:32 ` [PATCH 2/5] make /dev/kmem return error for highmem Dave Hansen
2013-04-11 9:58 ` Borislav Petkov
2013-04-10 23:32 ` [PATCH 3/5] avoid /dev/kmem oopses with DEBUG_VIRTUAL Dave Hansen
2013-04-10 23:32 ` [PATCH 4/5] break up slow_virt_to_phys() Dave Hansen
2013-04-11 12:29 ` Borislav Petkov
2013-04-11 16:28 ` Dave Hansen
2013-04-11 17:12 ` Borislav Petkov [this message]
2013-04-10 23:32 ` [PATCH 5/5] keep /dev/kmem from triggering BUG_ON() with DEBUG_VIRTUAL Dave Hansen
2013-04-11 12:37 ` Borislav Petkov
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=20130411171246.GF27062@pd.tnic \
--to=bp@alien8.de \
--cc=dave@sr71.net \
--cc=hpa@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=x86@kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.