linux-kernel - Re: [PATCH 1/5] afs: Fix afs_server

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Date:   Fri, 17 Nov 2023 11:57:33 -0400
From:   Marc Dionne <marc.dionne@...istor.com>
To:     David Howells <dhowells@...hat.com>
Cc:     linux-afs@...ts.infradead.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] afs: Fix afs_server_list to be cleaned up with RCU

On Thu, Nov 16, 2023 at 11:53 AM David Howells <dhowells@...hat.com> wrote:
>
> afs_server_list is accessed with the rcu_read_lock() held from
> volume->servers, so it needs to be cleaned up correctly.
>
> Fix this by using kfree_rcu() instead of kfree().
>
> Fixes: 8a070a964877 ("afs: Detect cell aliases 1 - Cells with root volumes")
> Signed-off-by: David Howells <dhowells@...hat.com>
> cc: Marc Dionne <marc.dionne@...istor.com>
> cc: linux-afs@...ts.infradead.org
> ---
>  fs/afs/internal.h    | 1 +
>  fs/afs/server_list.c | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/afs/internal.h b/fs/afs/internal.h
> index c9cef3782b4a..a812952be1c9 100644
> --- a/fs/afs/internal.h
> +++ b/fs/afs/internal.h
> @@ -553,6 +553,7 @@ struct afs_server_entry {
>  };
>
>  struct afs_server_list {
> +       struct rcu_head         rcu;
>         afs_volid_t             vids[AFS_MAXTYPES]; /* Volume IDs */
>         refcount_t              usage;
>         unsigned char           nr_servers;
> diff --git a/fs/afs/server_list.c b/fs/afs/server_list.c
> index ed9056703505..b59896b1de0a 100644
> --- a/fs/afs/server_list.c
> +++ b/fs/afs/server_list.c
> @@ -17,7 +17,7 @@ void afs_put_serverlist(struct afs_net *net, struct afs_server_list *slist)
>                 for (i = 0; i < slist->nr_servers; i++)
>                         afs_unuse_server(net, slist->servers[i].server,
>                                          afs_server_trace_put_slist);
> -               kfree(slist);
> +               kfree_rcu(slist, rcu);
>         }
>  }

Reviewed-by: Marc Dionne <marc.dionne@...istor.com>

Marc