Re: [PATCH] nfs: fix memory leak in error path of nfs4_do_reclaim

[Trond Myklebust <trondmy@kernel.org>]

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@huawei.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.

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