Re: [patch] mm: close page_mkwrite races (try 3)

[Nick Piggin <npiggin@suse.de>]

On Tue, Apr 28, 2009 at 11:57:39AM -0700, Ravikiran G Thirumalai wrote:
> On Wed, Apr 15, 2009 at 06:38:47PM -0700, Andrew Morton wrote:
> >On Wed, 15 Apr 2009 10:25:07 +0200 Nick Piggin <npiggin@suse.de> wrote:
> >
> >> - Trond for NFS (http://bugzilla.kernel.org/show_bug.cgi?id=12913).
> >
> >I wonder which kernel version(s) we should put this in.
> >
> >Going BUG isn't nice, but that report is against 2.6.27.  Is the BUG
> >super-rare, or did we avoid it via other means, or what?
> >
> 
> Jumping in late in  after being bit by this bug many times
> over with  2.6.27.  The bug (http://bugzilla.kernel.org/show_bug.cgi?id=12913)
> is not rare with the right workload at all.

Good data point, thanks.


> I can easily make it happen on smp machines, when multiple
> processes are writing to the same NFS mounted file system.  AFAICT this
> needs to be back ported to 27 stable and 29 stable as well.
> 
> Nick, are there 27 based patches already available someplace?
> Obviously, I have verified these patches + Trond's patch --
> http://lkml.org/lkml/2009/4/25/64 fixes the issue with 2.6.30-rc3

I haven't got any prepared, but they should be a pretty trivial
backport, provided we also backport c2ec175c39f62949438354f603f4aa170846aabb
(which is probably a good idea anyway).

However I will probably wait for a bit, given that the patch isn't upstream
yet.