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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-06-05 15:51:18 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-06-05 15:51:18 +0300
commit57caf4ec2b8bfbcb4f738ab5a12eedf3a8786045 (patch)
tree19d5662b5b54fe439eeb62520f021ff71eabf30d /drivers/cpufreq
parent33fc30b470983e5b641a16cccc882f6777dd50ef (diff)
downloadlinux-57caf4ec2b8bfbcb4f738ab5a12eedf3a8786045.tar.xz
cpufreq: intel_pstate: Avoid division by 0 in min_perf_pct_min()
Commit c5a2ee7dde89 (cpufreq: intel_pstate: Active mode P-state limits rework) incorrectly assumed that pstate.turbo_pstate would always be nonzero for CPU0 in min_perf_pct_min() if cpufreq_register_driver() had succeeded which may not be the case in virtualized environments. If that assumption doesn't hold, it leads to an early crash on boot in intel_pstate_register_driver(), so add a sanity check to min_perf_pct_min() to prevent the crash from happening. Fixes: c5a2ee7dde89 (cpufreq: intel_pstate: Active mode P-state limits rework) Reported-and-tested-by: Jongman Heo <jongman.heo@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/intel_pstate.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index b7de5bd76a31..eb1158532de3 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -571,9 +571,10 @@ static inline void update_turbo_state(void)
static int min_perf_pct_min(void)
{
struct cpudata *cpu = all_cpu_data[0];
+ int turbo_pstate = cpu->pstate.turbo_pstate;
- return DIV_ROUND_UP(cpu->pstate.min_pstate * 100,
- cpu->pstate.turbo_pstate);
+ return turbo_pstate ?
+ DIV_ROUND_UP(cpu->pstate.min_pstate * 100, turbo_pstate) : 0;
}
static s16 intel_pstate_get_epb(struct cpudata *cpu_data)