Date: Sat, 27 Aug 2005 12:49:41 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: rwatson@FreeBSD.org Cc: bzeeb-lists@lists.zabbadoz.net, freebsd-current@FreeBSD.org, dandee@volny.cz Subject: Re: LOR route vr0 Message-ID: <20050827.124941.14976142.imp@bsdimp.com> In-Reply-To: <20050827184153.A24510@fledge.watson.org> References: <20050827181827.O24510@fledge.watson.org> <20050827.114013.35047360.imp@bsdimp.com> <20050827184153.A24510@fledge.watson.org>
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In message: <20050827184153.A24510@fledge.watson.org> Robert Watson <rwatson@FreeBSD.org> writes: : : On Sat, 27 Aug 2005, M. Warner Losh wrote: : : > : Generally speaking, network interface device driver locks follow network : > : stack locks in the lock order. However, I've not really looked much at : > : the route table locking so can't speak to whether that is the case : > : specifically for routing locks. If it is, the below traces reflect the : > : correct order, and you might want to add a hard-coded entry to witness in : > : order to catch the reverse order. : > : > Can you pose a quickie summary on how to do that? I tried last night and : > was unsuccessful... : : You need to add an entry to subr_witness.c creating a graph edge between : the softc lock and the routing lock. An example of an entry in : subr_witness.c: : : /* : * TCP/IP : */ : { "tcp", &lock_class_mtx_sleep }, : { "tcpinp", &lock_class_mtx_sleep }, : { "so_snd", &lock_class_mtx_sleep }, : { NULL, NULL }, : : Note that sets of ordered entries are terminated with a double-null. This : declares that locks of type "tcp" preceed "tcpinp" which preceed : "so_snd". So you have to have locks of type tcp BEFORE you take out tcpinp type locks? Warner
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