Date: Sat, 16 Oct 2010 20:11:10 +0000 (UTC) From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r213932 - head/sys/netinet Message-ID: <20101016195748.E10185@maildrop.int.zabbadoz.net> In-Reply-To: <201010161953.o9GJrN4q088035@svn.freebsd.org> References: <201010161953.o9GJrN4q088035@svn.freebsd.org>
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On Sat, 16 Oct 2010, Bjoern A. Zeeb wrote: > Author: bz > Date: Sat Oct 16 19:53:22 2010 > New Revision: 213932 > URL: http://svn.freebsd.org/changeset/base/213932 > > Log: > MfP4 CH182763 (original version): > > Make it harder to exploit certain in_control() related races between the > intiial lookup at the beginning and the time we will remove the entry > from the lists by re-checking that entry is still in the list before > trying to remove it. > > (*) It is believed that with the current code and locking strategy we > cannot completely fix all race. Just as a follow-up: a couple of weeks ago I spent too much time on this to come to that conclusion. Try running 3 or more parallel ifconfig loops adding and removing the very same address and it's only matter of seconds. In case someone is interested I have a way huger patch of unknown state around but it's always only shifiting the problem. A possibly better fix to change the locking strategy is currently under discussion. > Reported by: Nima Misaghian (nima_misa hotmail.com) on net@ 20100817 > Tested by: Nima Misaghian (nima_misa hotmail.com) (original version) > PR: kern/146250 > Submitted by: Mikolaj Golub (to.my.trociny gmail.com) (different version) > MFC after: 1 week > > Modified: > head/sys/netinet/in.c -- Bjoern A. Zeeb Welcome a new stage of life.
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