[PATCH] nvme-rdma: Avoid double freeing of async event data

From: Prabhath Sajeepa
Date: Mon Mar 09 2020 - 17:08:04 EST


The timeout of identify cmd, which is invoked as part of admin queue
creation, can result in freeing of async event data both in
nvme_rdma_timeout handler and error handling path of
nvme_rdma_configure_admin queue thus causing NULL pointer reference.
Call Trace:
? nvme_rdma_setup_ctrl+0x223/0x800 [nvme_rdma]
nvme_rdma_create_ctrl+0x2ba/0x3f7 [nvme_rdma]
nvmf_dev_write+0xa54/0xcc6 [nvme_fabrics]
__vfs_write+0x1b/0x40
vfs_write+0xb2/0x1b0
ksys_write+0x61/0xd0
__x64_sys_write+0x1a/0x20
do_syscall_64+0x60/0x1e0
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Prabhath Sajeepa <psajeepa@xxxxxxxxxxxxxxx>
Reviewed-by: Roland Dreier <roland@xxxxxxxxxxxxxxx>
---
drivers/nvme/host/rdma.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 3e85c5c..0fe08c4 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -850,9 +850,11 @@ static int nvme_rdma_configure_admin_queue(struct nvme_rdma_ctrl *ctrl,
if (new)
blk_mq_free_tag_set(ctrl->ctrl.admin_tagset);
out_free_async_qe:
- nvme_rdma_free_qe(ctrl->device->dev, &ctrl->async_event_sqe,
- sizeof(struct nvme_command), DMA_TO_DEVICE);
- ctrl->async_event_sqe.data = NULL;
+ if (ctrl->async_event_sqe.data) {
+ nvme_rdma_free_qe(ctrl->device->dev, &ctrl->async_event_sqe,
+ sizeof(struct nvme_command), DMA_TO_DEVICE);
+ ctrl->async_event_sqe.data = NULL;
+ }
out_free_queue:
nvme_rdma_free_queue(&ctrl->queues[0]);
return error;
--
2.7.4