[PATCH V2] nvme-rdma: fix double free in nvme_rdma_free_queue

From: Jianchao Wang
Date: Thu May 10 2018 - 05:41:53 EST


BUG: KASAN: double-free or invalid-free in nvme_rdma_free_queue+0xf6/0x110 [nvme_rdma]
Workqueue: nvme-reset-wq nvme_rdma_reset_ctrl_work [nvme_rdma]
Call Trace:
dump_stack+0x91/0xeb
print_address_description+0x6b/0x290
kasan_report_invalid_free+0x55/0x80
__kasan_slab_free+0x176/0x190
kfree+0xeb/0x310
nvme_rdma_free_queue+0xf6/0x110 [nvme_rdma]
nvme_rdma_configure_admin_queue+0x1a3/0x4d0 [nvme_rdma]
nvme_rdma_reset_ctrl_work+0x4e/0xd0 [nvme_rdma]
process_one_work+0x3ca/0xaa0
worker_thread+0x4e2/0x6c0
kthread+0x18d/0x1e0
ret_from_fork+0x24/0x30

The double free is on ctrl->async_event_sqe.
If any case fails before ctrl->async_event_sqe is allocated in
nvme_rdma_configure_admin_queue, nvme_rdma_free_queue will be
invoked. However, at the moment, the ctrl->async_event_sqe has
not been allocated because it has been freed in
nvme_rdma_reset_ctrl_work
-> nvme_rdma_shutdown_ctrl
->nvme_rdma_destroy_admin_queue
-> nvme_rdma_free_queue

Signed-off-by: Jianchao Wang <jianchao.w.wang@xxxxxxxxxx>
---

V2:
handle it in nvme_rdma_free_queue and add some comment to explain it.

drivers/nvme/host/rdma.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 966e0dd..fa5cf87 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -561,9 +561,18 @@ static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
return;

if (nvme_rdma_queue_idx(queue) == 0) {
- nvme_rdma_free_qe(queue->device->dev,
- &queue->ctrl->async_event_sqe,
- sizeof(struct nvme_command), DMA_TO_DEVICE);
+ /*
+ * async_event_sqe is not allocated in nvme_rdma_alloc_queue.
+ * so there are cases where NVME_RDMA_Q_ALLOCATED is set, but
+ * async_event_sqe is not allocated. To avoid double free, set
+ * async_event_sqe.data to NULL to indicate it has been freed.
+ */
+ if (queue->ctrl->async_event_sqe.data) {
+ nvme_rdma_free_qe(queue->device->dev,
+ &queue->ctrl->async_event_sqe,
+ sizeof(struct nvme_command), DMA_TO_DEVICE);
+ queue->ctrl->async_event_sqe.data = NULL;
+ }
}

nvme_rdma_destroy_queue_ib(queue);
--
2.7.4