[ Upstream commit d1bcf006a9d3d63c1bcb65a993cb13756954cd9c ] nvme_round_robin_path() should test if the return ns pointer is valid. nvme_next_ns() will return a NULL pointer if there is no path left. Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy") Signed-off-by: Daniel Wagner <dwagner@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <sashal@kernel.org>