5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chuck Lever <chuck.lever@xxxxxxxxxx>
[ Upstream commit 1e02c641c3a43c88cecc08402000418e15578d38 ]
@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")
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/nfsd/nfs4callback.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 4eae2c5af2edf..18d62d3424c1a 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1379,6 +1379,8 @@ 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) {
--
2.43.0
