Questions about locking; turnstiles and sleeping threads

[Alfred Perlstein]

On 11/13/14, 1:09 AM, Adrian Chadd wrote:
> On 13 November 2014 00:59, Alfred Perlstein <alfred at freebsd.org> wrote:
>> On 11/12/14, 11:25 PM, Adrian Chadd wrote:
>>> On 12 November 2014 19:48, Adrian Chadd <adrian at freebsd.org> wrote:
>>>> kan pointed out that we should likely do a WITNESS_WARN() in the
>>>> relevant spots in the callout code so we catch these before it
>>>> happens.
>>>>
>>>> I'll see what we can add to -HEAD to be pro-active about it.
>>> Amusingly, I tried adding it and it made my laptop turn to soup very
>>> quickly - among other things, the TCP timer callouts are all setup
>>> with non sleep locks held.
>>>
>> Howso?  You only have to worry about callout_drain(), most other callout
>> functions should be safe-ish....
> yeah, except for all the places where they drain the timer once
> something happens so it doesn't fire.
>
> :)

What is the backtrace...?