linux-kernel - Re: [PATCH] nfs: fix memory leak in error path of nfs4_do

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Message-ID: <CAFX2Jf=H=ia5Cq6nk3zK_Z22H=5ehDC+NPE8TRyAB1QY4eKV9g@mail.gmail.com>
Date: Wed, 4 Sep 2024 16:15:49 -0400
From: Anna Schumaker <anna@...nel.org>
To: Trond Myklebust <trondmy@...nel.org>
Cc: Li Lingfeng <lilingfeng3@...wei.com>, jlayton@...nel.org, linux-nfs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, yukuai1@...weicloud.com, houtao1@...wei.com, 
	yi.zhang@...wei.com, yangerkun@...wei.com, lilingfeng@...weicloud.com
Subject: Re: [PATCH] nfs: fix memory leak in error path of nfs4_do_reclaim

On Wed, Sep 4, 2024 at 10:39 AM Trond Myklebust <trondmy@...nel.org> wrote:
>
> On Wed, 2024-09-04 at 20:34 +0800, Li Lingfeng wrote:
> > Commit c77e22834ae9 ("NFSv4: Fix a potential sleep while atomic in
> > nfs4_do_reclaim()") separate out the freeing of the state owners from
> > nfs4_purge_state_owners() and finish it outside the rcu lock.
> > However, the error path is omitted. As a result, the state owners in
> > "freeme" will not be released.
> > Fix it by adding freeing in the error path.
> >
> > Fixes: c77e22834ae9 ("NFSv4: Fix a potential sleep while atomic in
> > nfs4_do_reclaim()")
> > Signed-off-by: Li Lingfeng <lilingfeng3@...wei.com>
> > ---
> >  fs/nfs/nfs4state.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
> > index 877f682b45f2..30aba1dedaba 100644
> > --- a/fs/nfs/nfs4state.c
> > +++ b/fs/nfs/nfs4state.c
> > @@ -1957,6 +1957,7 @@ static int nfs4_do_reclaim(struct nfs_client
> > *clp, const struct nfs4_state_recov
> >                               set_bit(ops->owner_flag_bit, &sp-
> > >so_flags);
> >                               nfs4_put_state_owner(sp);
> >                               status =
> > nfs4_recovery_handle_error(clp, status);
> > +                             nfs4_free_state_owners(&freeme);
> >                               return (status != 0) ? status : -
> > EAGAIN;
> >                       }
> >
>
> Nice catch! Yes, that leak has been there for quite a while. Thanks for
> finding it.

Looks good to me, too. I've applied this for v6.12 (with a cc stable
so it gets backported)

Anna

>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@...merspace.com
>
>