Date: Wed, 19 Mar 2008 08:59:02 +0000 From: Doug Rabson <dfr@rabson.org> To: Jeff Roberson <jeff@FreeBSD.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern kern_lockf.c Message-ID: <485E42A7-7955-4E95-9887-DCAE664CD9AE@rabson.org> In-Reply-To: <200803190713.m2J7DOPp083103@repoman.freebsd.org> References: <200803190713.m2J7DOPp083103@repoman.freebsd.org>
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--Apple-Mail-59--23324358 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit On 19 Mar 2008, at 07:13, Jeff Roberson wrote: > jeff 2008-03-19 07:13:24 UTC > > FreeBSD src repository > > Modified files: > sys/kern kern_lockf.c > Log: > - Fix the last of the threading bugs that were introduced as far > back as > 1.38 in 2001. Break out of the FOREACH_THREAD_IN_PROC loop when > we've > discovered a new proc in the chain. > - Increment i and check for maxlockdepth once per matching process > not > once per thread. This didn't properly terminate the loop before. > - Fix a bug which has existed potentially since rev 1.1. > waitblock->lf_next > can be NULL when a thread has been woken-up but not yet > scheduled. Check > for this condition rather than blindly dereferencing. > > Found by: libMicro > > Revision Changes Path > 1.59 +12 -6 src/sys/kern/kern_lockf.c I have completely removed all this proc tomfoolery in my perforce branch and have replaced it with a real deadlock detection system instead of this horrible code. Apart from anything else, the existing code has serious locking problems - if the deadlock loop spans two or more vnodes, it doesn't lock any but the first one. I should have a patch ready for review (along with the new kernel NFS lock manager) towards the end of this week and I hope to get the thing into -current some time next week. --Apple-Mail-59--23324358--
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