NFSv4.1: protect destroying and nullifying bc_serv structure

When we are shutting down the client, we free the callback
server structure and then at a later pointer we free the
transport used by the client. Yet, it's possible that after
the callback server is freed, the transport receives a
backchannel request at which point we can dereferene freed
memory. Instead, do the freeing the bc server and nullying
bc_serv under the lock.

Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Olga Kornievskaia
2025-11-04 17:29:27 -05:00
committed by Trond Myklebust
parent 6f8b26c90a
commit 9e9fdd0ad0

View File

@@ -270,7 +270,7 @@ void nfs_callback_down(int minorversion, struct net *net, struct rpc_xprt *xprt)
if (cb_info->users == 0) {
svc_set_num_threads(serv, NULL, 0);
dprintk("nfs_callback_down: service destroyed\n");
svc_destroy(&cb_info->serv);
xprt_svc_destroy_nullify_bc(xprt, &cb_info->serv);
}
mutex_unlock(&nfs_callback_mutex);
}