Re: 3.0.0-rc2: Xen: powernow-k8: Kernel panic - not syncing: Attempted to kill init!

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Jun 14, 2011 at 02:13:33AM +0200, Tobias Diedrich wrote:
> Tobias Diedrich wrote:
> > Konrad Rzeszutek Wilk wrote:
> > > > [    5.523199] rtc_cmos 00:05: setting system clock to 2011-06-13 20:20:00 UTC (1307996400)
> > > > [    5.523400] powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3700+ (1 cpu cores) (version 2.20.00)
> > > > [    5.530956] powernow-k8: fid 0x2 (1000 MHz), vid 0x12
> > > > [    5.531072] powernow-k8: fid 0xa (1800 MHz), vid 0xa
> > > > [    5.531187] powernow-k8: fid 0xc (2000 MHz), vid 0x8
> > > > [    5.531301] powernow-k8: fid 0xe (2200 MHz), vid 0x8
> > > > [    5.531460] Marking TSC unstable due to cpufreq changes
> > > > [    5.531680] powernow-k8: fid trans failed, fid 0x2, curr 0x0
> > > > [    5.531802] BUG: unable to handle kernel paging request at ffff880807e07b78
> > > > [    5.531982] IP: [<ffffffff81479163>] cpufreq_stats_update+0x46/0x5b
> > > 
> > > For this one, you will have to fire out gdb and disassemble the code to
> > > figure out where it failed. Look for 'gdb vmlinux' and 'disassembly' on this
> > > mailing list - that should provide some hints.
> > 
> > Probably because of the 'fid trans failed' stat->last_index is -1
> 
> It's set to -1 in cpufreq_stats_create_table(), the second call to
> freq_table_get_index() doesn't check against -1 (expecting the call
> to always succeed):
> 
> 	stat->last_time = get_jiffies_64();
> 	stat->last_index = freq_table_get_index(stat, policy->cur);

What is policy->cur? Is is 800000 ? If so, does this fix your problem:

diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 83479b6..9be00d9 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1079,7 +1079,8 @@ static int transition_frequency_fidvid(struct powernow_k8_data *data,
        }
 
        res = transition_fid_vid(data, fid, vid);
-       freqs.new = find_khz_freq_from_fid(data->currfid);
+       if (!res)
+               freqs.new = find_khz_freq_from_fid(data->currfid);
 
        for_each_cpu(i, data->available_cores) {
                freqs.cpu = i;