5.4-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown neilb@suse.de
[ Upstream commit 7917f01a286ce01e9c085e24468421f596ee1a0c ]
A recent patch inadvertently broke callbacks for NFSv4.0.
In the 4.0 case we do not expect a session to be found but still need to call setup_callback_client() which will not try to dereference it.
This patch moves the check for failure to find a session into the 4.1+ branch of setup_callback_client()
Fixes: 1e02c641c3a4 ("NFSD: Prevent NULL dereference in nfsd4_process_cb_update()") Signed-off-by: NeilBrown neilb@suse.de Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs4callback.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index 55128de1a89d..d490f28aa7f6 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -878,7 +878,7 @@ static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *c args.authflavor = clp->cl_cred.cr_flavor; clp->cl_cb_ident = conn->cb_ident; } else { - if (!conn->cb_xprt) + if (!conn->cb_xprt || !ses) return -EINVAL; clp->cl_cb_session = ses; args.bc_xprt = conn->cb_xprt; @@ -1229,8 +1229,6 @@ 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) {