[PATCH 1/3] RDMA/rxe: Fix "kernel NULL pointer dereference" error

[yanjun.zhu@linux.dev]

From: Zhu Yanjun <yanjun.zhu@linux.dev>

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")
Reported-by: syzbot+ab99dc4c6e961eed8b8e@syzkaller.appspotmail.com
Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
---
 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 516bf9b95e48..f10b461b9963 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -797,7 +797,9 @@ static void rxe_qp_do_cleanup(struct work_struct *work)
 	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 && qp->req.task.arg)
+		__rxe_do_task(&qp->req.task);
+
 	if (qp->sq.queue) {
 		__rxe_do_task(&qp->comp.task);
 		__rxe_do_task(&qp->req.task);
-- 
2.31.1