Subject: Re: Stalls when starting a VSOCK listening socket: soft lockups, RCU stalls, timeout

From: Thomas Gleixner <[email-masked]>
Date: Tue, 10 Mar 2026 09:20:38 +0100

On Tue, Mar 10 2026 at 09:09, Thomas Gleixner wrote:
> On Mon, Mar 09 2026 at 13:23, Matthieu Baerts wrote:
> So the only circumstances where mm_cid_do_fixup_tasks_to_cpus() fails to
> do that are:
>
>    1) task->mm != mm.
>
> or
>
>    2) task is not longer in the task list w/o going through do_exit()

  or

     3) task->mm_cid.active == 0 again w/o going through do_exit()

> How the heck is either one of them possible?
>
> Just for the record. The picture Jiri decoded from the VM crash dump is
> exactly the same. One task is not listed.
>
> Confused
>
>         tglx