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nvmet-rdma: fix possible bad dereference when freeing rsps

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It is possible that the host connected and saw a cm established
event and started sending nvme capsules on the qp, however the
ctrl did not yet see an established event. This is why the
rsp_wait_list exists (for async handling of these cmds, we move
them to a pending list).

Furthermore, it is possible that the ctrl cm times out, resulting
in a connect-error cm event. in this case we hit a bad deref [1]
because in nvmet_rdma_free_rsps we assume that all the responses
are in the free list.

We are freeing the cmds array anyways, so don't even bother to
remove the rsp from the free_list. It is also guaranteed that we
are not racing anything when we are releasing the queue so no
other context accessing this array should be running.

[1]:
--
Workqueue: nvmet-free-wq nvmet_rdma_free_queue_work [nvmet_rdma]
[...]
pc : nvmet_rdma_free_rsps+0x78/0xb8 [nvmet_rdma]
lr : nvmet_rdma_free_queue_work+0x88/0x120 [nvmet_rdma]
 Call trace:
 nvmet_rdma_free_rsps+0x78/0xb8 [nvmet_rdma]
 nvmet_rdma_free_queue_work+0x88/0x120 [nvmet_rdma]
 process_one_work+0x1ec/0x4a0
 worker_thread+0x48/0x490
 kthread+0x158/0x160
 ret_from_fork+0x10/0x18
--

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This commit is contained in:
Sagi Grimberg 2024-05-08 10:53:06 +03:00 committed by Keith Busch
parent d15dcd0f1a
commit 73964c1d07
1 changed files with 4 additions and 12 deletions
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16
drivers/nvme/target/rdma.c
View file

@ -474,12 +474,8 @@ nvmet_rdma_alloc_rsps(struct nvmet_rdma_queue *queue)
return 0;
out_free:
while (--i >= 0) {
struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
list_del(&rsp->free_list);
nvmet_rdma_free_rsp(ndev, rsp);
}
while (--i >= 0)
nvmet_rdma_free_rsp(ndev, &queue->rsps[i]);
kfree(queue->rsps);
out:
return ret;
@ -490,12 +486,8 @@ static void nvmet_rdma_free_rsps(struct nvmet_rdma_queue *queue)
struct nvmet_rdma_device *ndev = queue->dev;
int i, nr_rsps = queue->recv_queue_size * 2;
for (i = 0; i < nr_rsps; i++) {
struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
list_del(&rsp->free_list);
nvmet_rdma_free_rsp(ndev, rsp);
}
for (i = 0; i < nr_rsps; i++)
nvmet_rdma_free_rsp(ndev, &queue->rsps[i]);
kfree(queue->rsps);
}