5.4-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ 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@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfs4callback.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c index 771733396eab2..51462f7958b3c 100644 --- a/fs/nfsd/nfs4callback.c +++ b/fs/nfsd/nfs4callback.c @@ -1229,6 +1229,8 @@ 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) {