On Thu, Jul 22, 2021 at 05:42:55PM -0600, Jens Axboe wrote:

quoted

So how can we possibly get there with tsk->files == NULL and what does it
have to do with files, anyway?

It's not the clearest, but the files check is just to distinguish between
exec vs normal cancel. For exec, we pass in files == NULL. It's not
related to task->files being NULL or not, we explicitly pass NULL for
exec.

Er...  So turn that argument into bool cancel_all, and pass false on exit and
true on exit?  While we are at it, what happens if you pass io_uring descriptor
to another process, close yours and then have the recepient close the one it
has gotten?  AFAICS, io_ring_ctx_wait_and_kill(ctx) will be called in context
of a process that has never done anything io_uring-related.  Can it end up
trying to resubmit some requests?

I rather hope it can't happen, but I don't see what would prevent it...