Date: Thu, 13 Nov 2014 01:13:50 -0800 From: Alfred Perlstein <alfred@freebsd.org> To: Adrian Chadd <adrian@freebsd.org> Cc: "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: Questions about locking; turnstiles and sleeping threads Message-ID: <5464764E.9080308@freebsd.org> In-Reply-To: <CAJ-VmomQdNDWqdC7o-nuGfypDDgDsJX9ouhx%2Br7ckZptgzQ10Q@mail.gmail.com> References: <CAJ-VmomrauhCMoF_dZfMWWhZp0EgwfE9RmxL5Pc37PhLSzZ6Qg@mail.gmail.com> <20141112212613.21037929@kan> <CAJ-Vmok-8znyycyOBS_ZQU275zFy%2BzuZ2C-jt4N3DnuEVS=PWg@mail.gmail.com> <CAJ-Vmo=R4ayAn-d986TC3CzZ4y23jnDW=uTyo4O=x4Ae1wB60A@mail.gmail.com> <CAJ-Vmok40-W%2B%2BdUJPcfO74%2BuudCgbs3tR5nwrR-aNuCy=5o0HQ@mail.gmail.com> <546472DA.3080006@freebsd.org> <CAJ-VmomQdNDWqdC7o-nuGfypDDgDsJX9ouhx%2Br7ckZptgzQ10Q@mail.gmail.com>
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On 11/13/14, 1:09 AM, Adrian Chadd wrote: > On 13 November 2014 00:59, Alfred Perlstein <alfred@freebsd.org> wrote: >> On 11/12/14, 11:25 PM, Adrian Chadd wrote: >>> On 12 November 2014 19:48, Adrian Chadd <adrian@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...?
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