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Date:   Thu, 10 Feb 2022 17:38:22 -0800
From:   Luis Chamberlain <mcgrof@kernel.org>
To:     Stephen Rothwell <sfr@canb.auug.org.au>
Cc:     "Eric W. Biederman" <ebiederm@xmission.com>,
        Tong Zhang <ztong0001@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Domenico Andreoli <domenico.andreoli@linux.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Next Mailing List <linux-next@vger.kernel.org>
Subject: Re: linux-next: boottime warning from todays linux-next
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References: <20220210184340.7eba108a@canb.auug.org.au>
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Sender: Luis Chamberlain <mcgrof@infradead.org>
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On Fri, Feb 11, 2022 at 12:33:36PM +1100, Stephen Rothwell wrote:
> Hi Luis,
>=20
> On Thu, 10 Feb 2022 15:19:09 -0800 Luis Chamberlain <mcgrof@kernel.org> w=
rote:
> >=20
> > FWIW Linus merged a more newer version of the regression fix, and only
> > until today did we get that version on linux-next.
> >=20
> > > So it seems that the parent of "fs/binfmt_misc" is a permanently empty
> > > directory - the is_empty_dir() check in insert_header() succeeds. =20
> >=20
> > I am not seeing this issue on x86_64 KVM guest with:
> >=20
> > CONFIG_BINFMT_MISC=3Dm
> > or
> > CONFIG_BINFMT_MISC=3Dy
> >=20
> > I think the issue might be that linux-next has Andrew's earlier
> > version of the fix merged, and Linus now has the new version. So
> > linux-next has these extra things below. But I can't understand
> > why this is seen on ppc and not on x86_64.
> >=20
> > diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> > index 241cfc6bc36f..788b9a34d5ab 100644
> > --- a/kernel/sysctl.c
> > +++ b/kernel/sysctl.c
> > @@ -2735,17 +2735,6 @@ static struct ctl_table vm_table[] =3D {
> >  	{ }
> >  };
> > =20
> > -static struct ctl_table fs_table[] =3D {
> > -#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
> > -	{
> > -		.procname	=3D "binfmt_misc",
> > -		.mode		=3D 0555,
> > -		.child		=3D sysctl_mount_point,
> > -	},
> > -#endif
> > -	{ }
> > -};
> > -
> >  static struct ctl_table debug_table[] =3D {
> >  #ifdef CONFIG_SYSCTL_EXCEPTION_TRACE
> >  	{
> > @@ -2765,7 +2754,6 @@ static struct ctl_table dev_table[] =3D {
> > =20
> >  DECLARE_SYSCTL_BASE(kernel, kern_table);
> >  DECLARE_SYSCTL_BASE(vm, vm_table);
> > -DECLARE_SYSCTL_BASE(fs, fs_table);
> >  DECLARE_SYSCTL_BASE(debug, debug_table);
> >  DECLARE_SYSCTL_BASE(dev, dev_table);
> > =20
> > @@ -2773,7 +2761,6 @@ int __init sysctl_init_bases(void)
> >  {
> >  	register_sysctl_base(kernel);
> >  	register_sysctl_base(vm);
> > -	register_sysctl_base(fs);
> >  	register_sysctl_base(debug);
> >  	register_sysctl_base(dev);
> > =20
>=20
> Thanks for noticing that.  I have removed the old version from my copy
> of mmotm today.

And ... does that fix your boot?

  Luis