Re: [syzbot] [io-uring?] INFO: task hung in io_uring_del_tctx_node (5)

[Keith Busch]

On Mon, Oct 27, 2025 at 04:04:05PM -0600, Jens Axboe wrote:
> 
> commit 1cba30bf9fdd6c982708f3587f609a30c370d889
> Author: Keith Busch <kbusch@xxxxxxxxxx>
> Date:   Thu Oct 16 11:09:38 2025 -0700
> 
>     io_uring: add support for IORING_SETUP_SQE_MIXED
> 
> leaves fdinfo open up to being broken. Before, we had:
> 
> sq_entries = min(sq_tail - sq_head, ctx->sq_entries);
> 
> as a cap for the loop, now you just have:
> 
> while (sq_head < sq_tail) {
> 
> which seems like a bad idea. It's also missing an sq_head increment if
> we hit this condition:

This would have to mean the application did an invalid head ring-wrap,
right? Regardless, I messed up and the wrong thing will happen here in
that case as well as the one you mentioned.