1. 16 Jun, 2011 1 commit
    • Konrad Rzeszutek Wilk's avatar
      [CPUFREQ] Don't set stat->last_index to -1 if the pol->cur has incorrect value. · 46a310b8
      Konrad Rzeszutek Wilk authored
      If the driver submitted an non-existing pol>cur value (say it
      used the default initialized value of zero), when the cpufreq
      stats tries to setup its initial values it incorrectly sets
      stat->last_index to -1 (or 0xfffff...). And cpufreq_stats_update
      tries to update at that index location and fails.
      
      This can be caused by:
      
      stat->last_index = freq_table_get_index(stat, policy->cur);
      
      not finding the appropiate frequency in the table (b/c the policy->cur
      is wrong) and we end up crashing. The fix however is
      concentrated in the 'cpufreq_stats_update' as the last_index
      (and old_index) are updated there. Which means it can reset
      the last_index to -1 again and on the next iteration cause a crash.
      
      Without this patch, the following crash is observed:
      
      powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3700+ (1 cpu cores) (version 2.20.00)
      powernow-k8: fid 0x2 (1000 MHz), vid 0x12
      powernow-k8: fid 0xa (1800 MHz), vid 0xa
      powernow-k8: fid 0xc (2000 MHz), vid 0x8
      powernow-k8: fid 0xe (2200 MHz), vid 0x8
      Marking TSC unstable due to cpufreq changes
      powernow-k8: fid trans failed, fid 0x2, curr 0x0
      BUG: unable to handle kernel paging request at ffff880807e07b78
      IP: [<ffffffff81479163>] cpufreq_stats_update+0x46/0x5b
      .. snip..
      Pid: 1, comm: swapper Not tainted 3.0.0-rc2 #45 MICRO-STAR INTERNATIONAL CO., LTD MS-7094/MS-7094
      ..snip..
      Call Trace:
       [<ffffffff81479248>] cpufreq_stat_notifier_trans+0x48/0x7c
       [<ffffffff81095d68>] notifier_call_chain+0x32/0x5e
       [<ffffffff81095e6b>] __srcu_notifier_call_chain+0x47/0x63
       [<ffffffff81095e96>] srcu_notifier_call_chain+0xf/0x11
       [<ffffffff81477e7a>] cpufreq_notify_transition+0x111/0x134
       [<ffffffff8147b0d4>] powernowk8_target+0x53b/0x617
       [<ffffffff8147723a>] __cpufreq_driver_target+0x2e/0x30
       [<ffffffff8147a127>] cpufreq_governor_dbs+0x339/0x356
       [<ffffffff81477394>] __cpufreq_governor+0xa8/0xe9
       [<ffffffff81477525>] __cpufreq_set_policy+0x132/0x13e
       [<ffffffff8147848d>] cpufreq_add_dev_interface+0x272/0x28c
      Reported-by: default avatarTobias Diedrich <ranma+xen@tdiedrich.de>
      Tested-by: default avatarTobias Diedrich <ranma+xen@tdiedrich.de>
      Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Signed-off-by: default avatarDave Jones <davej@redhat.com>
      46a310b8
  2. 15 Jun, 2011 1 commit
  3. 14 Jun, 2011 27 commits
  4. 13 Jun, 2011 11 commits