Re: [PATCH] x86, perf_p4: block PMIs on init to prevent a stream of unkown NMIs

2014-01-20 Thread Don Zickus
On Mon, Jan 20, 2014 at 09:38:59AM +0100, Peter Zijlstra wrote: > On Fri, Jan 17, 2014 at 10:41:41AM -0500, Don Zickus wrote: > > I could have removed the ENABLE bit too, but was worried it would impact > > BIOS vendors secret ability to monitor cpu states. I figured the ability to > > generate a

Re: [PATCH] x86, perf_p4: block PMIs on init to prevent a stream of unkown NMIs

2014-01-20 Thread Peter Zijlstra
On Fri, Jan 17, 2014 at 10:41:41AM -0500, Don Zickus wrote: > I could have removed the ENABLE bit too, but was worried it would impact > BIOS vendors secret ability to monitor cpu states. I figured the ability to > generate a PMI or not is not interesting to them and chose that route instead. Yo

Re: [PATCH] x86, perf_p4: block PMIs on init to prevent a stream of unkown NMIs

2014-01-17 Thread Cyrill Gorcunov
On Fri, Jan 17, 2014 at 10:41:41AM -0500, Don Zickus wrote: > I tested this on a P4 we have in our lab. After two or three crashes, I could > normally reproduce the problem. Now after 10 crashes, everything continues > to boot correctly. > > Cc: Dave Young > Cc: Vivek Goyal > Cc: Cyrill Gorcun

[PATCH] x86, perf_p4: block PMIs on init to prevent a stream of unkown NMIs

2014-01-17 Thread Don Zickus
A bunch of unknown NMIs have popped up on a Pentium4 recently when booting into a kdump kernel. This was exposed because the watchdog timer went from 60 seconds down to 10 seconds (increasing the ability to reproduce this problem). What is happening is on boot up of the second kernel (the kdump o