On 3/13/2019 10:55 AM, Christoph Hellwig wrote:
From: James Smart <jsmart2021@xxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: James Smart <jsmart2021@xxxxxxxxx>
Reviewed-by: Ewan D. Milne <emilne@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/nvme/target/fc.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 1e9654f04c60..8d34aa573d5b 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -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;
}
V1 was checked in
(http://lists.infradead.org/pipermail/linux-nvme/2019-February/022193.html
V2 was skipped
(http://lists.infradead.org/pipermail/linux-nvme/2019-February/022540.html)
V2 changes the last
+ if (schedule_work(&assoc->del_work))
to
+ if (!schedule_work(&assoc->del_work))
Jens - can you do this manual fixup ?
-- james
