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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>
hifive-unleashed-5.1
James Smart 2019-03-13 18:55:03 +01:00 committed by Jens Axboe
parent 834d3710a0
commit 0191e7405b
1 changed files with 4 additions and 5 deletions
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9
drivers/nvme/target/fc.c
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@ -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);
nvmet_fc_tgt_a_put(assoc);
spin_lock_irqsave(&tgtport->lock, flags);
if (!schedule_work(&assoc->del_work))
nvmet_fc_tgt_a_put(assoc);
}
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;
}