[PATCH 5.10 29/79] nvmet: fix a use-after-free

Greg Kroah-Hartman
2022-09-13T14:56:08Z

From: Bart Van Assche <bvanassche@acm.org>

commit 6a02a61e81c231cc5c680c5dbf8665275147ac52 upstream.

Fix the following use-after-free complaint triggered by blktests nvme/004:

BUG: KASAN: user-memory-access in blk_mq_complete_request_remote+0xac/0x350
Read of size 4 at addr 0000607bd1835943 by task kworker/13:1/460
Workqueue: nvmet-wq nvme_loop_execute_work [nvme_loop]
Call Trace:
show_stack+0x52/0x58
dump_stack_lvl+0x49/0x5e
print_report.cold+0x36/0x1e2
kasan_report+0xb9/0xf0
__asan_load4+0x6b/0x80
blk_mq_complete_request_remote+0xac/0x350
nvme_loop_queue_response+0x1df/0x275 [nvme_loop]
__nvmet_req_complete+0x132/0x4f0 [nvmet]
nvmet_req_complete+0x15/0x40 [nvmet]
nvmet_execute_io_connect+0x18a/0x1f0 [nvmet]
nvme_loop_execute_work+0x20/0x30 [nvme_loop]
process_one_work+0x56e/0xa70
worker_thread+0x2d1/0x640
kthread+0x183/0x1c0
ret_from_fork+0x1f/0x30

Cc: stable@vger.kernel.org
Fixes: a07b4970f464 ("nvmet: add a generic NVMe target")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/nvme/target/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -730,6 +730,8 @@ static void nvmet_set_error(struct nvmet

static void __nvmet_req_complete(struct nvmet_req *req, u16 status)
{
+ struct nvmet_ns *ns = req->ns;
+
if (!req->sq->sqhd_disabled)
nvmet_update_sq_head(req);
req->cqe->sq_id = cpu_to_le16(req->sq->qid);
@@ -740,9 +742,9 @@ static void __nvmet_req_complete(struct

trace_nvmet_req_complete(req);

- if (req->ns)
- nvmet_put_namespace(req->ns);
req->ops->queue_response(req);
+ if (ns)
+ nvmet_put_namespace(ns);
}

void nvmet_req_complete(struct nvmet_req *req, u16 status)