Date: Wed, 19 Aug 2009 07:57:01 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-smp@freebsd.org Cc: Pramod Srinivasan <pramod@juniper.net> Subject: Re: LOCK_PROFILING Message-ID: <200908190757.01982.jhb@freebsd.org> In-Reply-To: <C6B0EA11.15AFC%Pramod@juniper.net> References: <C6B0EA11.15AFC%Pramod@juniper.net>
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On Wednesday 19 August 2009 2:30:25 am Pramod Srinivasan wrote: > Hi Folks, > > I have a difficult problem I am stuck with, we had ported LOCK_PROFILING to > FreeBSD 6.1 and is working fine on mips, but fails miserably on i386. > > Just enabling lock profiling by the sysctl causes the cpu to reset. > > root@bcdcpu3% sysctl debug.lock.prof.enable=1 > debug.lock.pr? << cpu resets here > > Has any one seen similar issues? Any pointers on where to start debugging > this issue? > > The suspicion is that the spin-lock is perhaps contributing to the problem, > but have not been able to get to the bottom. It sounds like a tripe fault. I suspect you are recursing on your stack somehow leading to a double fault that faults again trying to get a lock to output to the console perhaps (that would explain the lack of double fault messages if that were the case). Perhaps a lock used in the profiling is incorrectly being profiled? -- John Baldwin
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