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

[Eugene Grosbein]

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

From: Eugene Grosbein <egrosbein at rdtc.ru>
To: Andriy Gapon <avg at FreeBSD.org>
Cc: bug-followup at FreeBSD.org, Alexander Motin <mav at FreeBSD.org>
Subject: Re: kern/172166: Deadlock in the networking code, possible due to
 a bug in the SCHED_ULE
Date: Thu, 04 Oct 2012 13:12:22 +0700

 03.10.2012 21:56, Andriy Gapon ÐÉÛÅÔ:
 > 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.
 > 
 > 
 
 Can I have any advice/workaround/bugfix on how to reconfigure my routers
 to prevent them from locking this way?