Date: Fri, 14 Apr 2017 14:21:05 -0700 From: Maxim Sobolev <sobomax@freebsd.org> To: Peter Wemm <peter@wemm.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers <src-committers@freebsd.org>, Hiren Panchasara <hiren@freebsd.org> Subject: Re: svn commit: r316874 - head/sys/kern Message-ID: <CAH7qZftToe23-E05JVV0CUmFV2bu2zFuE_O6rmFObYbTdb1h4A@mail.gmail.com> In-Reply-To: <6942092.OsECkgAp13@overcee.wemm.org> References: <201704141723.v3EHNS3B043902@repo.freebsd.org> <12133324.zHp9vo75vZ@overcee.wemm.org> <CAH7qZfuxM2pWvPh-LGP8_vrSpm==hTCWjnoZoXSvaFSgAaS8pg@mail.gmail.com> <6942092.OsECkgAp13@overcee.wemm.org>
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Peter, It is actually the other way around. If you take syslogd code out of 11-stable and earlier that would work just fine with or without r316874. But since r285910 syslogd in head had been refactored a lot and I think that particular bug has introduced that has been masked by the shutdown() on datagram sockets becoming a NOP after r285910. Then r316874 restored our historical behavior for the shutdown(2) and bingo, bug in the new syslogd code is now causing it to spin when shutdown() != NOP. -Max On Fri, Apr 14, 2017 at 12:46 PM, Peter Wemm <peter@wemm.org> wrote: > On Friday, April 14, 2017 12:41:52 PM Maxim Sobolev wrote: > > Thanks, Peter. I will try to look into this asap. > > I don't understand what is going on yet. Presumably there must be other > changes in play that affect udp/select sometime between the original 2015 > change and this. The syslogd -s code is Old(TM). I'm also wondering > whether > the -s code even works at all since the 2015 / r285910 change... > > > -Max > > > > On Apr 14, 2017 12:32 PM, "Peter Wemm" <peter@wemm.org> wrote: > > > On Friday, April 14, 2017 11:49:26 AM Peter Wemm wrote: > > > > On Friday, April 14, 2017 05:23:28 PM Maxim Sobolev wrote: > > > > > Author: sobomax > > > > > Date: Fri Apr 14 17:23:28 2017 > > > > > New Revision: 316874 > > > > > URL: https://svnweb.freebsd.org/changeset/base/316874 > > > > > > > > > > Log: > > > > > Restore ability to shutdown DGRAM sockets, still forcing > ENOTCONN to > > > > > > be > > > > > > > > returned by the shutdown(2) system call. This ability has been > lost as > > > > > part > > > > > of the svn revision 285910. > > > > > > > > > > Reviewed by: ed, rwatson, glebius, hiren > > > > > MFC after: 2 weeks > > > > > Differential Revision: https://reviews.freebsd.org/D10351 > > > > > > > > This appears to have broken syslogd and had a major change in > behavior > > > > > > with > > > > > > > regards to select(2). > > > > > > > > If you run syslogd with the -s flag (which is default), it now spins > at > > > > > > 100% > > > > > > > cpu as all the shutdown sockets now return readable from select. > > > > > > > > Old releases / jails also manifest this behavor. If it wasn't for > > > > losing > > > > the ability to run old branch binaries I'd suggest changing syslogd > > > > instead, but we depend on this in the cluster and I expect others do > > > > too. > > > > > > > > I'm not 100% certain that this change is the culprit but a heads-up > > > > can't > > > > hurt. I'll try reverting it on the freebsd cluster next, after fixing > > > > the > > > > broken auditing changes. > > > > > > > > -Peter > > > > > > I can confirm that reverting r316874 fixes syslogd and backwards > > > compatability > > > with old branches. > > > > > > -- > > > Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com; > > > KI6FJV > > > UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246 > > -- > Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com; > KI6FJV > UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246 >
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