On 5/27/19 4:08 AM, Dan Carpenter wrote:
> Hello Jens Axboe,
>
> The patch f3fafe4103bd: "io_uring: add support for sqe links" from
> May 10, 2019, leads to the following static checker warning:
>
> fs/io_uring.c:623 io_req_link_next()
> error: potential NULL dereference 'nxt'.
>
> fs/io_uring.c
> 614 static void io_req_link_next(struct io_kiocb *req)
> 615 {
> 616 struct io_kiocb *nxt;
> 617
> 618 nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, list);
> 619 list_del(&nxt->list);
> ^^^^^^^^^
> The warning is a false positive but this is a NULL dereference.
>
> 620 if (!list_empty(&req->link_list)) {
> 621 INIT_LIST_HEAD(&nxt->link_list);
> ^^^^^
> False positive.
Both of them are false positives. I can work around them though, as it
probably makes it a bit cleaner, too.
>
> 622 list_splice(&req->link_list, &nxt->link_list);
> 623 nxt->flags |= REQ_F_LINK;
> 624 }
> 625
> 626 INIT_WORK(&nxt->work, io_sq_wq_submit_work);
> ^^^^^^^^^^
> 627 queue_work(req->ctx->sqo_wq, &nxt->work);
> ^^^^^^^^^^
> Other bugs.
Not sure what that means?
--
Jens Axboe
