From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chen Gang <gang.chen@asianux.com>
Subject: Re: [Suggestion] fs/namespace.c: the direct cause of the warning
 for: "ida_remove called for id=0 which is not allocated" with mnt_release_group_id()
Date: Fri, 24 May 2013 09:26:47 +0800
Message-ID: <519EC1D7.1000402@asianux.com>
References: <5191FE96.6050607@asianux.com> <20130523161805.1faa0f8c59bfc8ee728d8c7f@linux-foundation.org>
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Cc: Al Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Takashi Iwai <tiwai@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20130523161805.1faa0f8c59bfc8ee728d8c7f@linux-foundation.org>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

On 05/24/2013 07:18 AM, Andrew Morton wrote:
> On Tue, 14 May 2013 17:06:30 +0800 Chen Gang <gang.chen@asianux.com> =
wrote:
>=20
>> > After call collect_mounts(), then call drop_collected_mounts(), it=
 will
>> > report an warning: "ida_remove called for id=3D0 which is not allo=
cated"
>> > (one sample is audit_add_tree_rule() in kernel/audit_tree.c).
>> >=20
>> > The direct cause (maybe also be the root cause):
>> >   collect_mounts() passs 'CL_PRIVATE' to copy_tree() -> clone_mnt(=
).
>> >   it will set "mnt->mnt_group_id =3D 0" in clone_mnt().
>> >   when drop_collected_mounts() -> mnt_release_group_id(), 'mnt->mn=
t_group_id =3D=3D 0'.
> I expect this patch also addresses the bug.  Can you please review an=
d test it?
>=20

I am sure, after apply the patch below, it will be no warning again (fi=
x
the direct cause).

Originally, I want to fix this bug just like the patch below, but I am
not quite sure whether it will hide the real root cause.


Thanks.

>=20
> From: Takashi Iwai <tiwai@suse.de>
> Subject: vfs: fix invalid ida_remove() call
>=20
> When the group id of a shared mount is not allocated, the umount stil=
l
> tries to call mnt_release_group_id(), which eventually hits a kernel
> warning at ida_remove() spewing a message like:
>=20
>   ida_remove called for id=3D0 which is not allocated.
>=20
> This patch fixes the bug simply checking the group id in the caller.
>=20
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> Reported-by: Cristian Rodr=EF=BF=BDguez <crrodriguez@opensuse.org>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>=20
>  fs/pnode.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>=20
> diff -puN fs/pnode.c~vfs-fix-invalid-ida_remove-call fs/pnode.c
> --- a/fs/pnode.c~vfs-fix-invalid-ida_remove-call
> +++ a/fs/pnode.c
> @@ -83,7 +83,8 @@ static int do_make_slave(struct mount *m
>  		if (peer_mnt =3D=3D mnt)
>  			peer_mnt =3D NULL;
>  	}
> -	if (IS_MNT_SHARED(mnt) && list_empty(&mnt->mnt_share))
> +	if (mnt->mnt_group_id && IS_MNT_SHARED(mnt) &&
> +	    list_empty(&mnt->mnt_share))
>  		mnt_release_group_id(mnt);
> =20
>  	list_del_init(&mnt->mnt_share);
> _
>=20
>=20
>=20


--=20
Chen Gang

Asianux Corporation