linux-kernel - Re: [Stable-review] [0/3] 2.6.27.52 stable review

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: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 14 Aug 2010 07:43:35 +0200
From:	Willy Tarreau <w@....eu>
To:	Greg KH <gregkh@...e.de>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Grant Coady <gcoady.lk@...il.com>,
	linux-kernel@...r.kernel.org, stable@...nel.org,
	akpm@...ux-foundation.org, stable-review@...nel.org,
	alan@...rguk.ukuu.org.uk
Subject: Re: [Stable-review] [0/3] 2.6.27.52 stable review

On Fri, Aug 13, 2010 at 07:53:23PM -0700, Greg KH wrote:
> On Fri, Aug 13, 2010 at 05:51:56PM -0700, Linus Torvalds wrote:
> > On Fri, Aug 13, 2010 at 5:11 PM, Greg KH <gregkh@...e.de> wrote:
> > >
> > > That's a warning that current->mm is null.  I don't know enough about
> > > the mm subsystem to say if this is normal or not, and I don't at first
> > > glance, see how this patch could have caused this to happen.
> > 
> > We call that whole "expand_stack()" through handle_mm_fault(), and
> > that's _not_ called just for the process itself. So "current->mm" is
> > sometimes simply the wrong thing to use - like when you access the VM
> > of another process (during fork for the argument setup of the new VM,
> > or during ptrace etc).
> > 
> > Which is why I think commit 05fa199d45c should fix it. It makes the
> > stack expansion thing use the right mm. Which it just _happened_ to do
> > before, because it was always called just from the faulting code where
> > current->mm happened to be the right mm.
> > 
> > But I really don't know if there might be other issues lurking too.
> 
> Ok, I'll go add that commit, and I unpacked my older machine that runs
> the .27 kernel and will beat on it with that box tomorrow to see if
> anything else pops up.

Greg, I confirm that 05fa199d45c fixes the warnings. I did not have them
in .51, got them with .52-rc1 and got rid of it with the patch above.

Regards,
Willy

--
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/