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From: "David Xu" <davidxu@freebsd.org>
To: "Terry Lambert" <tlambert2@mindspring.com>
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Date: Fri, 30 May 2003 18:00:22 +0800
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cc: Bryan Liesner <bleez@verizon.net>
cc: freebsd-current@freebsd.org
Subject: Re: panic: kern/52718
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----- Original Message -----=20
From: "Terry Lambert" <tlambert2@mindspring.com>
To: "David Xu" <davidxu@freebsd.org>
Cc: "Bryan Liesner" <bleez@verizon.net>; <freebsd-current@freebsd.org>
Sent: Friday, May 30, 2003 5:27 PM
Subject: Re: panic: kern/52718


> David Xu wrote:
> > > This was caused by rev. 1.3 of a commit by Jeff Robertson to
> > > kern_utmx.c.  The problem is that the proc struct is not locked
> > > for:
> > >
> > >         FOREACH_THREAD_IN_PROC(td->td_proc, td0)
> > >
> > > in the lock and unlock.
> > >
> > > Either lock the proc before and unlock it after this, in both
> > > _utmx_lock() and _utmx_unlock(), or revert the code to 1.2.
> >=20
> > kern_sig.c has same issue in several places.
>=20
> Just looked... YUCK!  The Process group code and the code in
> the filt_sigdetach() have got to be what you are talking about,
> right?
>=20
Yes. :(

> I'm constantly surprised at some of the race windows I find in
> production code (not just FreeBSD), that are just waiting there
> to chew someone's leg off the first chance they get... 8-(.
>=20

Welcome to fix it.

> -- Terry
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