[PATCH 5.4 134/255] RDMA/rxe: Fix "kernel NULL pointer dereference" error

[Greg Kroah-Hartman]

From: Zhu Yanjun <yanjun.zhu@xxxxxxxxx>

[ Upstream commit a625ca30eff806395175ebad3ac1399014bdb280 ]

When rxe_queue_init in the function rxe_qp_init_req fails,
both qp->req.task.func and qp->req.task.arg are not initialized.

Because of creation of qp fails, the function rxe_create_qp will
call rxe_qp_do_cleanup to handle allocated resource.

Before calling __rxe_do_task, both qp->req.task.func and
qp->req.task.arg should be checked.

Fixes: 8700e3e7c485 ("Soft RoCE driver")
Link: https://lore.kernel.org/r/20220822011615.805603-2-yanjun.zhu@xxxxxxxxx
Reported-by: syzbot+ab99dc4c6e961eed8b8e@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Zhu Yanjun <yanjun.zhu@xxxxxxxxx>
Reviewed-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
Reviewed-by: Bob Pearson <rpearsonhpe@xxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_qp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
index 57f111fe5443..be3eff792864 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -805,7 +805,9 @@ void rxe_qp_destroy(struct rxe_qp *qp)
 	rxe_cleanup_task(&qp->comp.task);
 
 	/* flush out any receive wr's or pending requests */
-	__rxe_do_task(&qp->req.task);
+	if (qp->req.task.func)
+		__rxe_do_task(&qp->req.task);
+
 	if (qp->sq.queue) {
 		__rxe_do_task(&qp->comp.task);
 		__rxe_do_task(&qp->req.task);
-- 
2.35.1