Re: [PATCH 09/10] kthread: Ensure struct kthread is present for all kthreads
From: Eric W. Biederman <hidden>
Date: 2021-12-23 03:35:22
Also in:
linux-arch, lkml
Added a couple of people from the vhost thread. Linus Torvalds [off-list ref] writes:
On Wed, Dec 22, 2021 at 3:25 PM Eric W. Biederman [off-list ref] wrote:quoted
Solve this by skipping the put_user for all kthreads.Ugh. While this fixes the problem, could we please just not mis-use that 'set_child_tid' as that kthread pointer any more? It was always kind of hacky. I think a new pointer with the proper 'struct kthread *' type would be an improvement. One of the "arguments" in the comment for re-using that set_child_tid pointer was that 'fork()' used to not wrongly copy it, but your patch literally now does that "allocate new kthread struct" at fork-time, so that argument is actually bogus now.
I agree. I think I saw in the recent vhost patches that were generalizing create_io_thread that the pf_io_worker field of struct task_struct was being generalized as well. If so I think it makes sense just to take that approach. Just build some basic infrastructure that can be used for io_workers, vhost_workers, and kthreads. Eric _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization