[PATCH] nvme: fix potential invalid pointer dereference

[Maurizio Lombardi]

If nvme_alloc_admin_tag_set() fails, the admin_q and fabrics_q pointers
are left with an invalid, non-NULL value;
Other functions may then check the pointers' value and dereference them,
like it happens in
nvme_probe() -> out_disable: -> nvme_dev_remove_admin().

Fix the bug by setting admin_q and fabrics_q to NULL in case of error.
Also fix a NULL pointer dereference (the ctrl->admin_tagset pointer
is only initialized just before returning success;
therefore, in the error code path, blk_mq_free_tag_set() must be
called against the "set" variable).

Signed-off-by: Maurizio Lombardi <mlombard at redhat.com>
---
 drivers/nvme/host/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7be562a4e1aa..6b277b80a09c 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4921,7 +4921,9 @@ int nvme_alloc_admin_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 	blk_mq_destroy_queue(ctrl->admin_q);
 	blk_put_queue(ctrl->admin_q);
 out_free_tagset:
-	blk_mq_free_tag_set(ctrl->admin_tagset);
+	blk_mq_free_tag_set(set);
+	ctrl->admin_q = NULL;
+	ctrl->fabrics_q = NULL;
 	return ret;
 }
 EXPORT_SYMBOL_GPL(nvme_alloc_admin_tag_set);
-- 
2.31.1