LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: David Miller <davem@davemloft.net>
Cc: mikpe@it.uu.se, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [BUG] 2.6.25-rc3 hangs in early boot on Sun Ultra5
Date: Wed, 27 Feb 2008 09:02:22 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.1.00.0802270858450.7583@apollo.tec.linutronix.de> (raw)
In-Reply-To: <20080226.170613.107688605.davem@davemloft.net>

On Tue, 26 Feb 2008, David Miller wrote:
> What the FUTEX checking code is doing now is doing a "user" access
> with set_fs(KERNEL_DS) since it runs from the kernel bootup early init
> sequence.  And this is illegal according to the existing checks.
> 
> When we do set_fs(KERNEL_DS) then pass a "user" pointer down
> into a system call or something like that, we give it a pointer
> that "cannot fault".  So if we get into the fault handling
> path here for a case like that we really do want to scream and
> print out an OOPS message in my opinion.

So it would be correct to set_fs(USER_DS) then do the check and switch
back to KERNEL_DS ?
 
> I realize that not many platforms other than sparc64 can check
> for things this precisely, but it's something to consider.

Hmm, I missed that.
 
> Did this FUTEX change go into -stable too?

It's queued, AFAIK

Thanks,
	tglx

  reply	other threads:[~2008-02-27  8:02 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-25 20:41 Mikael Pettersson
2008-02-26  8:55 ` Mikael Pettersson
2008-02-26 21:32   ` David Miller
2008-02-27  0:49   ` David Miller
2008-02-27  1:06     ` David Miller
2008-02-27  8:02       ` Thomas Gleixner [this message]
2008-02-27 19:05         ` David Miller
2008-02-27 19:55           ` Thomas Gleixner
2008-02-27 19:16       ` Mikael Pettersson
2008-02-27 19:37         ` David Miller
2008-02-27  8:27     ` Mikael Pettersson
2008-02-26 20:46 ` David Miller

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=alpine.LFD.1.00.0802270858450.7583@apollo.tec.linutronix.de \
    --to=tglx@linutronix.de \
    --cc=davem@davemloft.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mikpe@it.uu.se \
    --cc=sparclinux@vger.kernel.org \
    --subject='Re: [BUG] 2.6.25-rc3 hangs in early boot on Sun Ultra5' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).