[PATCH 2/2] afs: Fix access after dec in put functions
Marc Dionne
marc.dionne at auristor.com
Tue Aug 2 10:27:20 PDT 2022
On Tue, Aug 2, 2022 at 2:15 PM David Howells <dhowells at redhat.com> wrote:
>
> Marc Dionne <marc.dionne at auristor.com> wrote:
>
> > > - trace_afs_server(server, r - 1, atomic_read(&server->active), reason);
> > > + trace_afs_server(server->debug_id, r - 1, a, reason);
> >
> > Don't you also want to copy server->debug_id into a local variable here?
>
> Okay, how about the attached change?
>
> David
> ---
> diff --git a/fs/afs/server.c b/fs/afs/server.c
> index bca4b4c55c14..4981baf97835 100644
> --- a/fs/afs/server.c
> +++ b/fs/afs/server.c
> @@ -399,7 +399,7 @@ struct afs_server *afs_use_server(struct afs_server *server, enum afs_server_tra
> void afs_put_server(struct afs_net *net, struct afs_server *server,
> enum afs_server_trace reason)
> {
> - unsigned int a;
> + unsigned int a, debug_id = server->debug_id;
> bool zero;
> int r;
>
> @@ -408,7 +408,7 @@ void afs_put_server(struct afs_net *net, struct afs_server *server,
>
> a = atomic_inc_return(&server->active);
> zero = __refcount_dec_and_test(&server->ref, &r);
> - trace_afs_server(server->debug_id, r - 1, a, reason);
> + trace_afs_server(debug_id, r - 1, a, reason);
> if (unlikely(zero))
> __afs_put_server(net, server);
> }
Looks fine with that change.
Marc
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