threads/103127: Kernel panic while using thread features in Squid 2.6

[John-Mark Gurney]

The following reply was made to PR kern/103127; it has been noted by GNATS.

From: John-Mark Gurney <gurney_j at resnet.uoregon.edu>
To: Anders Nordby <anders at fupp.net>
Cc: FreeBSD-gnats-submit at FreeBSD.org, freebsd-threads at FreeBSD.org,
        Thomas-Martin Seck <tmseck at netcologne.de>,
        Suleiman Souhlal <ssouhlal at FreeBSD.org>
Subject: Re: threads/103127: Kernel panic while using thread features in Squid 2.6
Date: Sat, 16 Sep 2006 13:50:44 -0700

 Anders Nordby wrote this message on Wed, Sep 13, 2006 at 20:58 +0200:
 > After talking with Pawel, I tried the attached patch to get some kqueue
 > debug info. I just got it:
 > 
 > Sep 13 20:18:56 cache3 kernel: NULL f_event in new kn
 > Sep 13 20:18:56 cache3 kernel: f_event == NULL
 
 This means that the f_attach method for that event isn't setting f_event
 properly...  We need to figure out which event this is happening w/...
 
 Try the following modifications:
 > --- sys/kern/kern_event.c.orig	Wed Sep 13 08:44:57 2006
 > +++ sys/kern/kern_event.c	Wed Sep 13 08:51:03 2006
 > @@ -900,6 +900,8 @@
 >  				goto done;
 >  			}
 >  			KN_LIST_LOCK(kn);
 > +			if (kn->kn_fop->f_event == NULL)
  {
 > +				printf("NULL f_event in new kn\n");
 			printf("kn: ident: %d, filter: %d\n", kn->kn_ident, kn->kn_filter);
 }
 >  		} else {
 >  			/*
 >  			 * The user may change some filter values after the
 
 I have a feeling that this is a similar panic that jhb is seeing...
 Which means that filter will be EVFILT_VNODE (-4)...
 
 -- 
   John-Mark Gurney				Voice: +1 415 225 5579
 
      "All that I will do, has been done, All that I have, has not."