Date: Fri, 22 Sep 2006 13:13:37 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: John Baldwin <john@baldwin.cx> Cc: anders@freebsd.org, freebsd-threads@freebsd.org Subject: Re: kern/103127: Kernel panic while using thread features in Squid 2.6 Message-ID: <20060922201336.GT23915@funkthat.com> In-Reply-To: <200609221425.02723.john@baldwin.cx> References: <200609202105.k8KL5fh7081141@freefall.freebsd.org> <200609212152.31366.john@baldwin.cx> <20060922023748.GR23915@funkthat.com> <200609221425.02723.john@baldwin.cx>
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John Baldwin wrote this message on Fri, Sep 22, 2006 at 14:25 -0400:
> On Thursday 21 September 2006 22:37, John-Mark Gurney wrote:
> > John Baldwin wrote this message on Thu, Sep 21, 2006 at 21:52 -0400:
> > > On Wednesday 20 September 2006 17:05, John-Mark Gurney wrote:
> > > > Synopsis: Kernel panic while using thread features in Squid 2.6
> > > >
> > > > State-Changed-From-To: open->feedback
> > > > State-Changed-By: jmg
> > > > State-Changed-When: Wed Sep 20 21:04:55 UTC 2006
> > > > State-Changed-Why:
> > > > waiting for people to test the patch of badfo_kqfilter that is attached
> > > > to the bug..
> > >
> > > Should it possibly return EBADF rather than EINVAL?
> >
> > If we got this far, we have to have a valid fd, maybe ENXIO?
>
> badfo_* are used for bad (invalid) file descriptors. :) All the other badfo_*
> functions return EBADF (except for poll, since it returns an event mask
> rather than an errno).
except we did have a valid fd since we did an fget on the
descriptor, and that would fail if it was bad:
if ((fp = fget_locked(fdp, fd)) == NULL || fp->f_ops == &badfileops) {
FILEDESC_UNLOCK(fdp);
return (EBADF);
}
or can f_ops change in the middle?
>From my reading it looks like it can can during a close, but if the
application is doing a simultanious close and attaching a knote, that's
a race condition, and we techincally still have a valid fd till was
can't fget the fd anymore... just MO of course...
--
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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