[PATCH 5.4 43/76] nvmet-rdma: Fix list_del corruption on queue establishment failure

From: Greg Kroah-Hartman
Date: Mon Jan 18 2021 - 14:11:25 EST

From: Israel Rukshin <israelr@xxxxxxxxxx>

[ Upstream commit 9ceb7863537748c67fa43ac4f2f565819bbd36e4 ]

When a queue is in NVMET_RDMA_Q_CONNECTING state, it may has some
requests at rsp_wait_list. In case a disconnect occurs at this
state, no one will empty this list and will return the requests to
free_rsps list. Normally nvmet_rdma_queue_established() free those
requests after moving the queue to NVMET_RDMA_Q_LIVE state, but in
this case __nvmet_rdma_queue_disconnect() is called before. The
crash happens at nvmet_rdma_free_rsps() when calling
list_del(&rsp->free_list), because the request exists only at
the wait list. To fix the issue, simply clear rsp_wait_list when
destroying the queue.

Signed-off-by: Israel Rukshin <israelr@xxxxxxxxxx>
Reviewed-by: Max Gurtovoy <mgurtovoy@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/nvme/target/rdma.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index b5314164479e9..50e2007092bc0 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -1351,6 +1351,16 @@ static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
spin_lock_irqsave(&queue->state_lock, flags);
switch (queue->state) {
+ while (!list_empty(&queue->rsp_wait_list)) {
+ struct nvmet_rdma_rsp *rsp;
+ rsp = list_first_entry(&queue->rsp_wait_list,
+ struct nvmet_rdma_rsp,
+ wait_list);
+ list_del(&rsp->wait_list);
+ nvmet_rdma_put_rsp(rsp);
+ }
+ fallthrough;
disconnect = true;