linux-kernel - Re: [PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps regression

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Message-ID: <854e01e2-9c17-2050-9113-a399acdefde2@oracle.com>
Date:   Mon, 29 May 2023 11:11:43 -0500
From:   michael.christie@...cle.com
To:     Oleg Nesterov <oleg@...hat.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux@...mhuis.info, nicolas.dichtel@...nd.com, axboe@...nel.dk,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, mst@...hat.com,
        sgarzare@...hat.com, jasowang@...hat.com, stefanha@...hat.com,
        brauner@...nel.org
Subject: Re: [PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps
 regression

On 5/29/23 6:19 AM, Oleg Nesterov wrote:
> If we want CLONE_THREAD, I think vhost_worker() should exit after get_signal()
> returns SIGKILL. Perhaps it should "disable" vhost_work_queue() somehow and
> flush the pending works on ->work_list before exit, I dunno. But imo it should
> not wait for the final fput().

Just a FYI, I coded this. It's pre-RFC quality. It's invasive. If we want to go
this route then we have to do a temp hack for 6.4 or revert then do this route
for 6.5 or 6.6 (vhost devs will need time to review and we need time to full test).