Showing error 852

User: Jiri Slaby
Error type: Resource Leak
Error type description: The code omits to put the resource to the system for reuse
File location: arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
Line in file: 278
Project: Linux Kernel
Project version: 2.6.28
Tools: Stanse (1.2)
Entered: 2011-11-07 22:40:13 UTC

Source: 

248 * to this function.
249 * Input: cpu number
250 * Return: Average CPU frequency in terms of max frequency (zero on error)
251 *
252 * We use IA32_MPERF and IA32_APERF MSRs to get the measured performance
253 * over a period of time, while CPU is in C0 state.
254 * IA32_MPERF counts at the rate of max advertised frequency
255 * IA32_APERF counts at the rate of actual CPU frequency
256 * Only IA32_APERF/IA32_MPERF ratio is architecturally defined and
257 * no meaning should be associated with absolute values of these MSRs.
258 */
259static unsigned int get_measured_perf(struct cpufreq_policy *policy,
260                                      unsigned int cpu)
261{
262        union {
263                struct {
264                        u32 lo;
265                        u32 hi;
266                } split;
267                u64 whole;
268        } aperf_cur, mperf_cur;
269
270        cpumask_t saved_mask;
271        unsigned int perf_percent;
272        unsigned int retval;
273
274        saved_mask = current->cpus_allowed;
275        set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
276        if (get_cpu() != cpu) {
277                /* We were not able to run on requested processor */
278                put_cpu();
279                return 0;
280        }
281
282        rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi);
283        rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi);
284
285        wrmsr(MSR_IA32_APERF, 0,0);
286        wrmsr(MSR_IA32_MPERF, 0,0);
287
288#ifdef __i386__
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