lkml.org 
[lkml]   [2007]   [Feb]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] perfmon ia64: fix file/vma lifetime
Nick,

On Tue, Feb 20, 2007 at 04:08:45PM +0100, Nick Piggin wrote:
> On Tue, Feb 20, 2007 at 06:34:54AM -0800, Stephane Eranian wrote:
> > nick,
> >
> > On Tue, Feb 20, 2007 at 03:18:56PM +0100, Nick Piggin wrote:
> > > From: Nick Piggin <npiggin@suse.de>
> > >
> > > Perfmon associates vmalloc()ed memory with a file descriptor, and installs
> > > a vma mapping that memory. Unfortunately, the vm_file field is not filled in,
> > > so processes with mappings to that memory do not prevent the file from being
> > > closed and the memory freed. This results in use-after-free bugs and multiple
> > > freeing of pages, etc.
> > >
> > > I saw this bug on an Altix on SLES9. Haven't reproduced upstream but it looks
> > > like the same issue is there.
> > >
> >
> > I think this is possible for the old perfmon v2.0 codebase that is currently in
> > mainline for IA-64.
>
> OK, I take that as an Ack? (the patch definitely applies, I just can't
> get the Altix to boot 2.6.20 to verify it).
>
> > I have corrected this with the multi-arch v2.3 code base
> > available as a kernel patch for the moment.
>
> Not that I've looked at the code, but can I be hopeful that v2.3
> using the traditional mmap file operation to set up the vma and map
> in pages, rather than the way that v2.0 works?
>

It does. You need an explicit mmap() call.

--

-Stephane
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-02-20 16:17    [from the cache]
©2003-2011 Jasper Spaans