Date: Thu, 27 May 1999 10:32:00 -0400 From: "David E. Cross" <crossd@cs.rpi.edu> To: Dmitrij Tejblum <tejblum@arc.hq.cti.ru> Cc: "David E. Cross" <crossd@cs.rpi.edu>, hackers@FreeBSD.ORG, crossd@cs.rpi.edu Subject: Re: kernel debugging assistance Message-ID: <199905271432.KAA21944@cs.rpi.edu> In-Reply-To: Message from Dmitrij Tejblum <tejblum@arc.hq.cti.ru> of "Wed, 26 May 1999 18:39:05 %2B0400." <199905261439.SAA12649@arc.hq.cti.ru>
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> I don't think that this dump is useful for debugging this problem. Perhaps, if > you compile the kernel with DEBUG_LOCKS, you will get more useful info. > > Dima I checked through the source for DEBUG_LOCKS, it doesn't appear to do anything other than to printout information.... information that I already have access to by way of this dump file. I will turn it on regardless swo it makes my life a bit more simple. In looking through this, and at the program that used to cause this problem reliably (it no longer does, even though nothing changed on the client or workstation; I am guessing that it is a race condition that happens 5% of the time and I filled my quota for the next 20 years ;) I have a theory what is going on... NFS service is entirely in the kernel for FreeBSD, excepting the NFSDs which mostly sit arround to give the kernel contexts to pass requests into. NFS uses its own namei mechanism which requests a lock on what it is looking up. What if it gets 2 requests at about the same time for the same file. That would certainly seem a likely cause for this problem. I note that all the files that are causing this crash are files that would be accessed in the aforementioned behaviour; netscape cache files, .Xauthority-c, and the data file for the test prgram which is accessed rapidly and repeatedly. Does this seem like a reasonable theory to anyone? -- David Cross | email: crossd@cs.rpi.edu Systems Administrator/Research Programmer | Web: http://www.cs.rpi.edu/~crossd Rensselaer Polytechnic Institute, | Ph: 518.276.2860 Department of Computer Science | Fax: 518.276.4033 I speak only for myself. | WinNT:Linux::Linux:FreeBSD To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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