6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tristan Madani [ Upstream commit ef248d5de4469fb6bbaf8dbe0c4c47800080d648 ] nvme_alloc_ns() error path at out_unlink_ns removes ns from the namespace head siblings list with list_del_rcu(&ns->siblings) but does not wait for SRCU readers before freeing the namespace struct. Multipath code iterates the head->list under srcu_read_lock() in nvme_find_path() and nvme_mpath_revalidate_paths(), so a concurrent reader can still hold a reference to ns when kfree(ns) runs. The normal removal path in nvme_ns_remove() correctly calls synchronize_srcu(&ns->head->srcu) after list_del_rcu() to wait for in-progress readers. Add the same grace period in the error path. Fixes: ed754e5deeb1 ("nvme: track shared namespaces") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani Reviewed-by: Sagi Grimberg Reviewed-by: John Garry Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch [ Adjusted patch context to account for missing last_path reference-counting code. ] Signed-off-by: Sasha Levin --- drivers/nvme/host/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index d02ca033db439..c34ecb2c96562 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3699,6 +3699,9 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info) if (list_empty(&ns->head->list)) list_del_init(&ns->head->entry); mutex_unlock(&ctrl->subsys->lock); + + /* guarantee not available in head->list */ + synchronize_srcu(&ns->head->srcu); nvme_put_ns_head(ns->head); out_cleanup_disk: put_disk(disk); -- 2.53.0