nvme-rdma: fix possible use-after-free in transport error_recovery work

While nvme_rdma_submit_async_event_work is checking the ctrl and queue
state before preparing the AER command and scheduling io_work, in order
to fully prevent a race where this check is not reliable the error
recovery work must flush async_event_work before continuing to destroy
the admin queue after setting the ctrl state to RESETTING such that
there is no race .submit_async_event and the error recovery handler
itself changing the ctrl state.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 850f84d204d053632241bac939726584f965e290..9c55e4be8a3986b5d9e4115fffa1f42cbfa7e962 100644 (file)
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1200,6 +1200,7 @@ static void nvme_rdma_error_recovery_work(struct work_struct *work)
                        struct nvme_rdma_ctrl, err_work);
 
        nvme_stop_keep_alive(&ctrl->ctrl);
+       flush_work(&ctrl->ctrl.async_event_work);
        nvme_rdma_teardown_io_queues(ctrl, false);
        nvme_start_queues(&ctrl->ctrl);
        nvme_rdma_teardown_admin_queue(ctrl, false);