nvme: add missing SRCU grace period in error path

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 <tristan@talencesecurity.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

0 files changed, 0 insertions, 0 deletions