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From: Thomas Gleixner <>
To: David Miller <>
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: <> (raw)
In-Reply-To: <>

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


  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

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