On Mon, Aug 03, 2015 at 11:54:17PM +0200, Peter Zijlstra wrote: > On Mon, Aug 03, 2015 at 11:32:28PM +0200, Jiri Olsa wrote: > > hi, > > I'm getting following message on the kdump kernel start > > > > Broken BIOS detected, complain to your hardware vendor.\ > > [Firmware Bug]: the BIOS has corrupted hw-PMU resources (MSR 38d is b0) > > > > it seems to be caused by NMI watchdog being configured > > and fixed counter values stays in MSRs, which triggers > > warning in check_hw_exists and disables perf support > > in kdump kernel.. which probably does not hurt ;-) > > > > zeroing MSRs during kdump shutdown seems to work (attached) > > but I'm not sure thats correct place for kdump perf callback > > Right, but why bother? All that kernel needs to do is write a memory > dump to someplace and reboot, right? The less you do, the less can go > wrong. well, I was hunting that 'Broken BIOS..' message which is wrong I wouldn't think anyone wants to use perf under kdump kernel, but you never know ;-) jirka
