@@ -189,16 +189,22 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
return 0;
pd = em_cpu_get(cpu);
- if (!pd)
+ if (!pd) {
+ cpufreq_cpu_put(policy);
return -EINVAL;
+ }
dtpm = per_cpu(dtpm_per_cpu, cpu);
- if (dtpm)
+ if (dtpm) {
+ cpufreq_cpu_put(policy);
return power_add(dtpm, pd);
+ }
dtpm = dtpm_alloc(&dtpm_ops);
- if (!dtpm)
+ if (!dtpm) {
+ cpufreq_cpu_put(policy);
return -EINVAL;
+ }
dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
if (!dtpm_cpu)
@@ -226,6 +232,7 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
if (ret)
goto out_power_sub;
+ cpufreq_cpu_put(policy);
return 0;
out_power_sub:
@@ -243,6 +250,7 @@ static int cpuhp_dtpm_cpu_online(unsigned int cpu)
out_kfree_dtpm:
kfree(dtpm);
+ cpufreq_cpu_put(policy);
return ret;
}
In line 186(#1), 'policy = cpufreq_cpu_get(cpu)' will increase the kobject reference counter of the policy. The policy has to be released with the help of 'cpufreq_cpu_put()' to balance its kobject reference counter properly. However, the function returns without dropping the reference (#2,#3,#4,#5 and #6). It may result in a reference leak bug. It can be fixed by calling the function 'cpufreq_cpu_put()' before the function returns. 178 static int cpuhp_dtpm_cpu_online(unsigned int cpu) 179 { ... 186 policy = cpufreq_cpu_get(cpu); //#1 reference increase ... 191 if (!pd) 192 return -EINVAL; //#2 function returns without decrementing reference counter 193 194 dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); 195 if (dtpm_cpu) 196 return dtpm_update_power(&dtpm_cpu->dtpm); //#3 function returns without decrementing reference counter 197 198 dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL); 199 if (!dtpm_cpu) 200 return -ENOMEM; //#4 function returns without decrementing reference counter ... 220 return 0; //#5 function returns without decrementing reference counter ... 226 out_kfree_dtpm_cpu: ... 231 return ret; //#6 function returns without decrementing reference counter 232 } Signed-off-by: Wentao_Liang <Wentao_Liang_g@163.com> --- drivers/powercap/dtpm_cpu.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)