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From:   Ilya Dryomov <idryomov@gmail.com>
Date:   Wed, 15 Nov 2023 13:32:38 +0100
Message-ID: <CAOi1vP9TnF+BWiEauddskmTO_+V2uvHiqpEg5EoxzZPKb0oEAQ@mail.gmail.com>
Subject: Re: [PATCH] ceph: quota: Fix invalid pointer access in
To:     Xiubo Li <xiubli@redhat.com>
Cc:     Wenchao Hao <haowenchao2@huawei.com>,
        Jeff Layton <jlayton@kernel.org>, ceph-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org, louhongxiang@huawei.com
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On Wed, Nov 15, 2023 at 1:35=E2=80=AFAM Xiubo Li <xiubli@redhat.com> wrote:
>
>
> On 11/14/23 23:31, Wenchao Hao wrote:
> > This issue is reported by smatch, get_quota_realm() might return
> > ERR_PTR, so we should using IS_ERR_OR_NULL here to check the return
> > value.
> >
> > Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
> > ---
> >   fs/ceph/quota.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
> > index 9d36c3532de1..c4b2929c6a83 100644
> > --- a/fs/ceph/quota.c
> > +++ b/fs/ceph/quota.c
> > @@ -495,7 +495,7 @@ bool ceph_quota_update_statfs(struct ceph_fs_client=
 *fsc, struct kstatfs *buf)
> >       realm =3D get_quota_realm(mdsc, d_inode(fsc->sb->s_root),
> >                               QUOTA_GET_MAX_BYTES, true);
> >       up_read(&mdsc->snap_rwsem);
> > -     if (!realm)
> > +     if (IS_ERR_OR_NULL(realm))
> >               return false;
> >
> >       spin_lock(&realm->inodes_with_caps_lock);
>
> Good catch.
>
> Reviewed-by: Xiubo Li <xiubli@redhat.com>
>
> We should CC the stable mail list.

Hi Xiubo,

What exactly is being fixed here?  get_quota_realm() is called with
retry=3Dtrue, which means that no errors can be returned -- EAGAIN, the
only error that get_quota_realm() can otherwise generate, would be
handled internally by retrying.

Am I missing something that makes this qualify for stable?

Thanks,

                Ilya