It crashes all the same

New backtrace attached - looks very similar to the old one, although
not identical.

On Mon, Feb 10, 2020 at 10:25 PM Jens Axboe <axboe@kernel.dk> wrote:
>
> On 2/10/20 6:22 PM, Glauber Costa wrote:
> > Hello my dear io_uring friends
> >
> > Today I tried to run my tests on a different, more powerful hardware
> > (70+ Hyperthreads) and it crashed on creating the ring.
> >
> > I don't recall anything fancy in my code for creating the ring -
> > except maybe that I size the cq ring differently than the sq ring.
> >
> > The backtrace attached leads me to believe that we just accessed a
> > null struct somewhere
>
> Yeah, but it's in the alloc code, it's not in io-wq/io_uring.
> Here's where it is crashing:
>
> struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
> {
>         [...]
>         for_each_node(node) {
>                 struct io_wqe *wqe;
>
>                 wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, node);
>
> I guess the node isn't online, and that's why it's crashing. Try the
> below for starters, it should get it going.
>
>
> diff --git a/fs/io-wq.c b/fs/io-wq.c
> index 182aa17dc2ca..3898165baccb 100644
> --- a/fs/io-wq.c
> +++ b/fs/io-wq.c
> @@ -1115,8 +1116,11 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
>
>         for_each_node(node) {
>                 struct io_wqe *wqe;
> +               int alloc_node = node;
>
> -               wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, node);
> +               if (!node_online(alloc_node))
> +                       alloc_node = NUMA_NO_NODE;
> +               wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
>                 if (!wqe)
>                         goto err;
>                 wq->wqes[node] = wqe;
>
> --
> Jens Axboe
>