From: Sagi Grimberg Date: Wed, 8 May 2024 07:53:06 +0000 (+0300) Subject: nvmet-rdma: fix possible bad dereference when freeing rsps X-Git-Tag: nvme-6.9-2024-05-09^0 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=73964c1d07c054376f1b32a62548571795159148;p=nvme.git nvmet-rdma: fix possible bad dereference when freeing rsps 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 Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch --- diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c index 5b8c63e74639..6e1b4140cde0 100644 --- a/drivers/nvme/target/rdma.c +++ b/drivers/nvme/target/rdma.c @@ -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); }