Commit 0191e740 authored Mar 13, 2019 by James Smart Committed by Jens Axboe Mar 13, 2019

nvmet-fc: fix issues with targetport assoc_list list walking



There are two changes:

1) The logic in the __nvmet_fc_free_assoc() routine is bad. It uses
"safe" routines assuming pointers will come back valid.  However, the
intervening next structure being linked can be removed from the list and
the resulting safe pointers are bad, resulting in NULL ptrs being hit.

Correct by scheduling a work element to perform the association delete,
which can be done while under lock.

2) Prior patch that added the work element scheduling left a possible
reference on the object if the work element couldn't be scheduled.

Correct by doing the put on a failing schedule_work() call.

Signed-off-by: Nigel Kirkland <nigel.kirkland@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 834d3710

drivers/nvme/target/fc.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -1143,10 +1143,8 @@ __nvmet_fc_free_assocs(struct nvmet_fc_tgtport *tgtport)
		&tgtport->assoc_list, a_list) {
		if (!nvmet_fc_tgt_a_get(assoc))
		continue;
		spin_unlock_irqrestore(&tgtport->lock, flags);
		nvmet_fc_delete_target_assoc(assoc);
		if (!schedule_work(&assoc->del_work))
		nvmet_fc_tgt_a_put(assoc);
		spin_lock_irqsave(&tgtport->lock, flags);
		}
		spin_unlock_irqrestore(&tgtport->lock, flags);
		}
		@@ -1185,7 +1183,8 @@ nvmet_fc_delete_ctrl(struct nvmet_ctrl *ctrl)
		nvmet_fc_tgtport_put(tgtport);

		if (found_ctrl) {
		schedule_work(&assoc->del_work);
		if (!schedule_work(&assoc->del_work))
		nvmet_fc_tgt_a_put(assoc);
		return;
		}

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