Date: Sat, 24 Nov 2012 16:16:01 +0000 From: Attilio Rao <attilio@freebsd.org> To: Ryan Stone <rysto32@gmail.com> Cc: FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: Spurious witness warning when destroying spin mtx Message-ID: <CAJ-FndACSnqQAOU7-EtFr-wvY8MZazvXtup7sufhAyxCOg5RDQ@mail.gmail.com> In-Reply-To: <CAJ-FndCh4T-ezOnGEw8LEpE32LAfo4HM-FvbfOW8weEuOQV=7A@mail.gmail.com> References: <CAFMmRNyYccyXFh0r2jC2Q5ynYQH09SiZNguLp8X4JWSX4Lua5w@mail.gmail.com> <CAJ-FndDL18oQdFZQh4AKr9NbOc2WxWJoDVjOtkjt%2Bb7w36E_kA@mail.gmail.com> <CAFMmRNwn-d5P=hRxx9gyhNYJ%2B7ycVqzv-4FzXXvZGg0bC81REg@mail.gmail.com> <CAJ-FndCh4T-ezOnGEw8LEpE32LAfo4HM-FvbfOW8weEuOQV=7A@mail.gmail.com>
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On Sat, Nov 24, 2012 at 3:51 PM, Attilio Rao <attilio@freebsd.org> wrote: > On Sat, Nov 24, 2012 at 3:46 PM, Ryan Stone <rysto32@gmail.com> wrote: >> >> On Sat, Nov 24, 2012 at 10:01 AM, Attilio Rao <attilio@freebsd.org> wrote: >>> >>> I seriously wonder why right now we don't assume the lock is unheld. >>> There are likely historically reasons for that, but I would like to >>> know which one are those and eventually fix them out. >>> FWIK, all the other locking primitives assume the lock is already >>> unheld when destroying and I think it would be good to have that for >>> mutexes as well. >>> >>> Can you please show which lock triggers the panic you saw? >>> >>> Thanks, >>> Attilio >>> >> >> It was taskqueue_free: > > taskqueue_free() must not be called in places where there are still > races, so the lock is not really meaningful and should be acquired. Herm, I mean to say "after taskqueue_termintate() returns must not be races...". Attilio -- Peace can only be achieved by understanding - A. Einstein
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