Re: [PATCH] ceph: fix off by one bugs in unsafe_request_wait()

From: Ilya Dryomov <idryomov@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Jeff Layton <jlayton@kernel.org>, Xiubo Li <xiubli@redhat.com>,
	Ceph Development <ceph-devel@vger.kernel.org>,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] ceph: fix off by one bugs in unsafe_request_wait()
Date: Mon, 6 Sep 2021 20:03:24 +0200	[thread overview]
Message-ID: <CAOi1vP9bbs++zmcSJ=hb+PfR5-=QQbicHNNDu0uzcD_7XRG44g@mail.gmail.com> (raw)
In-Reply-To: <20210906094301.GB10957@kili>

On Mon, Sep 6, 2021 at 11:43 AM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> The "> max" tests should be ">= max" to prevent an out of bounds access
> on the next lines.
>
> Fixes: e1a4541ec0b9 ("ceph: flush the mdlog before waiting on unsafe reqs")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  fs/ceph/caps.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 26c5029629a4..ebbad9080422 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -2260,7 +2260,7 @@ static int unsafe_request_wait(struct inode *inode)
>                         list_for_each_entry(req, &ci->i_unsafe_dirops,
>                                             r_unsafe_dir_item) {
>                                 s = req->r_session;
> -                               if (unlikely(s->s_mds > max)) {
> +                               if (unlikely(s->s_mds >= max)) {
>                                         spin_unlock(&ci->i_unsafe_lock);
>                                         goto retry;
>                                 }
> @@ -2274,7 +2274,7 @@ static int unsafe_request_wait(struct inode *inode)
>                         list_for_each_entry(req, &ci->i_unsafe_iops,
>                                             r_unsafe_target_item) {
>                                 s = req->r_session;
> -                               if (unlikely(s->s_mds > max)) {
> +                               if (unlikely(s->s_mds >= max)) {
>                                         spin_unlock(&ci->i_unsafe_lock);
>                                         goto retry;
>                                 }
> --
> 2.20.1
>

Applied.

Thanks,

                Ilya