Re: [PATCH 1/1] hostfs: fix UML crash

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 18 Oct 2010 20:53:58 +0200
Richard Weinberger <richard@nod.at> wrote:

> Am Montag 18 Oktober 2010, 20:40:39 schrieb Andrew Morton:
> > On Mon, 18 Oct 2010 18:36:54 +0200 Richard Weinberger <richard@nod.at> 
> wrote:
> > > 365b1818 resized f_spare within struct statfs.
> > > hostfs accesses f_spare directly and needs an update.
> > > 
> > > Signed-off-by: Richard Weinberger <richard@nod.at>
> > > Reported-by: Toralf F__rster <toralf.foerster@gmx.de>
> > > Tested-by: Toralf F__rster <toralf.foerster@gmx.de>
> > > ---
> > > 
> > >  fs/hostfs/hostfs_user.c |    2 +-
> > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c
> > > index 6777aa0..ce2f168 100644
> > > --- a/fs/hostfs/hostfs_user.c
> > > +++ b/fs/hostfs/hostfs_user.c
> > > @@ -388,6 +388,6 @@ int do_statfs(char *root, long *bsize_out, long long
> > > *blocks_out,
> > > 
> > >  	spare_out[1] = buf.f_spare[1];
> > >  	spare_out[2] = buf.f_spare[2];
> > >  	spare_out[3] = buf.f_spare[3];
> > > 
> > > -	spare_out[4] = buf.f_spare[4];
> > > +
> > > 
> > >  	return 0;
> > >  
> > >  }
> > 
> > Thanks.
> > 
> > Is there any reason for hostfs to be playing with the f_spare field at all?
> 
> I'm not sure why hostfs is using this field.
> Currently I'm reviewing UML. 
> As soon I'm done with hostfs you'll receive a patch or an explanation. :-)

365b1818 added f_flags to `struct statfs' but didn't carry that over to
`struct compat_statfs' and hence didn't copy f_flags over into
compat_statfs.  Deliberate, or oversight?