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Date:   Sun, 28 May 2023 14:29:50 -0500
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Subject: Re: [PATCH 3/3] fork, vhost: Use CLONE_THREAD to fix freezer/ps
 regression
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     Oleg Nesterov <oleg@redhat.com>, linux@leemhuis.info,
        nicolas.dichtel@6wind.com, axboe@kernel.dk,
        torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, mst@redhat.com,
        sgarzare@redhat.com, jasowang@redhat.com, stefanha@redhat.com,
        brauner@kernel.org
References: <20230522025124.5863-1-michael.christie@oracle.com>
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 <20230522123029.GA22159@redhat.com>
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From:   Mike Christie <michael.christie@oracle.com>
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On 5/27/23 8:41 PM, Eric W. Biederman wrote:
> Mike Christie <michael.christie@oracle.com> writes:
> 
>> On 5/23/23 7:15 AM, Oleg Nesterov wrote:
>>>
>>> Now the main question. Whatever we do, SIGKILL/SIGSTOP/etc can come right
>>> before we call work->fn(). Is it "safe" to run this callback with
>>> signal_pending() or fatal_signal_pending() ?
>>
>> The questions before this one I'll leave for the core vhost devs since
>> they know best.
> 
> Let me ask a clarifying question:
> 
> Is it only the call to schedule() in vhost_worker that you are worried
> about not sleeping if signal_pending() or fatal_signal_pending()?

It will only be the vhost_worker call to schedule().

When we do the file_operation's release call, we normally set things up
so the work->fn just fails and cleans up. I can pretty easily move that
code into a helper and do:

if (get_signal(ksig))
	new_function_to_tell_drivers_that_all_work_fns_should_fail()