Date: Sun, 28 Mar 2010 16:10:38 -0700 From: Doug Barton <dougb@FreeBSD.org> To: Jilles Tjoelker <jilles@stack.nl> Cc: svn-src-stable@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, svn-src-stable-8@freebsd.org Subject: Re: svn commit: r205806 - stable/8/etc Message-ID: <4BAFE1EE.9040908@FreeBSD.org> In-Reply-To: <20100328210630.GA2086@stack.nl> References: <201003282019.o2SKJfPg033857@svn.freebsd.org> <4BAFBBFA.7020701@FreeBSD.org> <20100328210630.GA2086@stack.nl>
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On 03/28/10 14:06, Jilles Tjoelker wrote: > On Sun, Mar 28, 2010 at 01:28:42PM -0700, Doug Barton wrote: >> Probably my fault for not saying something sooner, but there is a >> problem with the code in head that sometimes causes it to loop >> repeatedly even though pwait exits successfully. I am trying to track it >> down, but since it only happens about once every 10 shutdowns it's been >> difficult. > > There is a difference between the two methods in what is waited for > exactly. pwait(1) will wait for the process to terminate; if it is > applied to a zombie it will return immediately (printing the exit status > if -v was given). On the other hand, kill(1) will continue to return > success until the process has been waited for by its parent. The process that I see this with most often is devd, does that fit the model you're describing? What are the implications of moving on after a successful pwait even though there is still a zombie process? > An obvious fix is to trust pwait if it returns successfully, e.g. like > if pwait $_list 2>/dev/null; then break; else sleep 2; fi It can't be break, the point of the loop is that wait_for_pids() takes a list. We may be able to use continue however. Doug -- ... and that's just a little bit of history repeating. -- Propellerheads Improve the effectiveness of your Internet presence with a domain name makeover! http://SupersetSolutions.com/
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