Date: Wed, 1 Sep 2004 16:56:54 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: Igor Sysoev <is@rambler-co.ru> Cc: freebsd-current@freebsd.org Subject: Re: panic caused by EVFILT_SIGNAL detaching in rfork()ed thread Message-ID: <20040901235654.GG29902@funkthat.com> In-Reply-To: <20040901224828.Q97970@is.park.rambler.ru> References: <20040901144705.K97970@is.park.rambler.ru> <20040901155304.GD29902@funkthat.com> <20040901173757.GF29902@funkthat.com> <20040901224828.Q97970@is.park.rambler.ru>
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Igor Sysoev wrote this message on Wed, Sep 01, 2004 at 23:07 +0400: > On Wed, 1 Sep 2004, John-Mark Gurney wrote: > > > > > The problem is some how that the knote is being removed from the list > > > > (or was never on the list), but not being marked detached... > > > > > > > > Hmmm. what are the options you are using for rfork? > > > > > > The worker process starts two worker threads created by > > > rfork(RFPROC|RFTHREAD|RFMEM). Each thread opens kqueue and > > > adds the EVFILT_SIGNAL event. > > > > > > If you like I can send to you the source tarball (I do not distribute > > > the server right now, because it has not the documentation). The build > > > process is simple. Then you need to press ^C and you will get the panic. > > > > I believe this panic may be possible w/o rfork, but I'm not possitive.. > > It's probably an artifact of the fact that the kq was living longer > > than the proc that had the signal kevent associated with it, which > > normally does not happen... > > > > Attached is a patch.. And let me know if it fixes your panic... > > The patch fixed the panic (I tested on 5.3-BETA2, GENERIC, SMP, HTT, > SCHED_ULE). Thank you. Could you make the similar patch for 4.x ? I'm not familar enough with kqueue in 4.x, so I would just add a similar if (kn->kn_status & KN_DETACHED) return; to the filt_sigdetach function like the other detach functions... > And one more, could you rename http://people.freebsd.org/~jmg/kqueue.man.html > into kqueue_preliminary.man.html and place a modern (or at least from > 4.1-RELEASE) kqueue man page in kqueue.man.html ? Google shows your > man page at first position and it confuses people. I saw several times > when people said that kqueue has the incompatible interface between BSDs > and even between various FreeBSD verisons referring to this man page. I've renamed it, but I will send admins an email to try to add a redirect so that broken links won't plauge the net... -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."
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