Date: Wed, 15 Feb 2012 12:30:17 GMT From: Eugene Grosbein <egrosbein@rdtc.ru> To: freebsd-net@FreeBSD.org Subject: Re: kern/162558: [dummynet] [panic] seldom dummynet panics Message-ID: <201202151230.q1FCUHAc037592@freefall.freebsd.org>
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The following reply was made to PR kern/162558; it has been noted by GNATS. From: Eugene Grosbein <egrosbein@rdtc.ru> To: bug-followup@FreeBSD.ORG Cc: Subject: Re: kern/162558: [dummynet] [panic] seldom dummynet panics Date: Wed, 15 Feb 2012 19:25:43 +0700 Hi! The source of this problem seems to be famous 'dangling pointer' problem: - mbufs with packets from PPPoE users sometimes stall within dummynet queues, - then user disconnects, its ngX interface get destroyed, - then dummynet attempts to dereference its ifp pointer and panic occurs. There is workaround consisting of several tunnables eliminating races: - net.isr.bindthreads=1 in /boot/loader.conf; - net.isr.direct=1 and net.isr.direct_force=1 in /etc/sysctl.conf (default) Plus, use recent 8.2-STABLE as it contains some netgraph fixes for bugs that lead to panics in 8.2-RELEASE and early 8.2-STABLE versions. With these precautions I run my routers rock stable for months. Eugene Grosbein
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