nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path

In nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected,
nvmet_req_uninit() is called unconditionally. However, if the command
arrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init()
had returned false and percpu_ref_tryget_live() was never executed. The
unconditional percpu_ref_put() inside nvmet_req_uninit() then causes a
refcount underflow, leading to a WARNING in
percpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and
eventually a permanent workqueue deadlock.

Check cmd->flags & NVMET_TCP_F_INIT_FAILED before calling
nvmet_req_uninit(), matching the existing pattern in
nvmet_tcp_execute_request().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shivam Kumar <kumar.shivam43666@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 4b8b02341ddc38a1940baaf8791c994fed9e3c78..69e971b179aeead7921297b136b42bbb9e8a099a 100644 (file)
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1310,7 +1310,8 @@ static int nvmet_tcp_try_recv_ddgst(struct nvmet_tcp_queue *queue)
                        queue->idx, cmd->req.cmd->common.command_id,
                        queue->pdu.cmd.hdr.type, le32_to_cpu(cmd->recv_ddgst),
                        le32_to_cpu(cmd->exp_ddgst));
-               nvmet_req_uninit(&cmd->req);
+               if (!(cmd->flags & NVMET_TCP_F_INIT_FAILED))
+                       nvmet_req_uninit(&cmd->req);
                nvmet_tcp_free_cmd_buffers(cmd);
                nvmet_tcp_fatal_error(queue);
                ret = -EPROTO;