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

[Mike Christie <michael.christie@oracle.com>]

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()