From: Chuck Lever <chuck.lever@xxxxxxxxxx>
@ses is initialized to NULL. If __nfsd4_find_backchannel() finds no
available backchannel session, setup_callback_client() will try to
dereference @ses and segfault.
Fixes: dcbeaa68dbbd ("nfsd4: allow backchannel recovery")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfsd/nfs4callback.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index d86a7b983785..2e18f635078f 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1500,6 +1500,8 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
ses = c->cn_session;
}
spin_unlock(&clp->cl_lock);
+ if (!c)
+ return;
err = setup_callback_client(clp, &conn, ses);
if (err) {
--
2.46.2
