Patch "nvme: use kref_get_unless_zero in nvme_find_get_ns" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

nvme: use kref_get_unless_zero in nvme_find_get_ns

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
nvme-use-kref_get_unless_zero-in-nvme_find_get_ns.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Christoph Hellwig <[email protected]>
Date: Wed, 18 Oct 2017 13:20:01 +0200
Subject: nvme: use kref_get_unless_zero in nvme_find_get_ns

From: Christoph Hellwig <[email protected]>

[ Upstream commit 2dd4122854f697afc777582d18548dded03ce5dd ]

For kref_get_unless_zero to protect against lookup vs free races we need to use it in all places where we aren't guaranteed to already hold a reference. There is no such guarantee in nvme_find_get_ns, so switch to kref_get_unless_zero in this function.

---
 drivers/nvme/host/core.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -2299,7 +2299,8 @@ static struct nvme_ns *nvme_find_get_ns(
 	mutex_lock(&ctrl->namespaces_mutex);
 	list_for_each_entry(ns, &ctrl->namespaces, list) {
 		if (ns->ns_id == nsid) {
-			kref_get(&ns->kref);
+			if (!kref_get_unless_zero(&ns->kref))
+				continue;
 			ret = ns;
 			break;
 		}

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/xfs-fix-incorrect-extent-state-in-xfs_bmap_add_extent_unwritten_real.patch queue-4.14/nvme-use-kref_get_unless_zero-in-nvme_find_get_ns.patch queue-4.14/target-iscsi-detect-conn_cmd_list-corruption-early.patch queue-4.14/target-iscsi-fix-a-race-condition-in-iscsit_add_reject_from_cmd.patch queue-4.14/scsi-core-fix-a-scsi_show_rq-null-pointer-dereference.patch queue-4.14/scsi-libsas-fix-length-error-in-sas_smp_handler.patch queue-4.14/blk-mq-sched-dispatch-from-scheduler-iff-progress-is-made-in-dispatch.patch