kern/172166: Deadlock in the networking code, possible due to a bug in the SCHED_ULE

[Andriy Gapon]

The following reply was made to PR kern/172166; it has been noted by GNATS.

From: Andriy Gapon <avg at FreeBSD.org>
To: bug-followup at FreeBSD.org
Cc: Alexander Motin <mav at FreeBSD.org>, eugen at eg.sd.rdtc.ru
Subject: Re: kern/172166: Deadlock in the networking code, possible due to
 a bug in the SCHED_ULE
Date: Wed, 03 Oct 2012 17:56:39 +0300

 on 02/10/2012 09:58 Alexander Motin said the following:
 > About rw_lock priority propagation locking(9) tells:
 > The rw_lock locks have priority propagation like mutexes, but priority can be
 > propagated only to an exclusive holder.  This limitation comes from the fact that
 > shared owners are anonymous.
 
 Yeah... and as we see it has a potential to result in priority inversion.
 
 > What's about idle stealing threshold, it was fixed in HEAD at r239194, but wasn't
 > merged yet. It should be trivial to merge it.
 
 And I've also misread the code, confused 6 CPUs case with 8 CPUs case.
 
 
 -- 
 Andriy Gapon