arch/x86/events/core.c:1869:25: warning: Local variable 'pmu' shadows outer variable [shadowVariable]

From: kernel test robot
Date: Mon Jul 25 2022 - 07:51:44 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: e0dccc3b76fb35bb257b4118367a883073d7390e
commit: a9c81ccdf52dd73a20178c40bca34cf52991fdea perf/x86: Add structures for the attributes of Hybrid PMUs
date: 1 year, 3 months ago
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce (cppcheck warning):
# apt-get install cppcheck
git checkout a9c81ccdf52dd73a20178c40bca34cf52991fdea
cppcheck --quiet --enable=style,performance,portability --template=gcc FILE

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

cppcheck warnings: (new ones prefixed by >>)
^
arch/x86/events/core.c:766:20: note: Using pointer that is a temporary.
if (WARN_ON_ONCE(!cpuc->pmu))
^
>> arch/x86/events/core.c:1869:25: warning: Local variable 'pmu' shadows outer variable [shadowVariable]
struct x86_hybrid_pmu *pmu;
^
arch/x86/events/core.c:48:19: note: Shadowed declaration
static struct pmu pmu;
^
arch/x86/events/core.c:1869:25: note: Shadow variable
struct x86_hybrid_pmu *pmu;
^

cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

^
arch/x86/events/core.c:766:20: note: Using pointer that is a temporary.
if (WARN_ON_ONCE(!cpuc->pmu))
^
arch/x86/events/core.c:769:9: warning: Using pointer that is a temporary. [danglingTemporaryLifetime]
return cpuc->pmu;
^
arch/x86/events/core.c:760:31: note: Address of variable taken here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:766:18: note: Assuming condition is false
if (WARN_ON_ONCE(!cpuc->pmu))
^
arch/x86/events/core.c:760:39: note: Temporary created here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:769:9: note: Using pointer that is a temporary.
return cpuc->pmu;
^
arch/x86/events/core.c:1561:56: warning: Using pointer that is a temporary. [danglingTemporaryLifetime]
pr_info("CPU#%d: active: %016llxn", cpu, *(u64 *)cpuc->active_mask);
^
arch/x86/events/core.c:1529:31: note: Address of variable taken here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1536:6: note: Assuming condition is false
if (!num_counters)
^
arch/x86/events/core.c:1529:39: note: Temporary created here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1561:56: note: Using pointer that is a temporary.
pr_info("CPU#%d: active: %016llxn", cpu, *(u64 *)cpuc->active_mask);
^
arch/x86/events/core.c:1577:35: warning: Using pointer that is a temporary. [danglingTemporaryLifetime]
if (fixed_counter_disabled(idx, cpuc->pmu))
^
arch/x86/events/core.c:1529:31: note: Address of variable taken here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1536:6: note: Assuming condition is false
if (!num_counters)
^
arch/x86/events/core.c:1529:39: note: Temporary created here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1577:35: note: Using pointer that is a temporary.
if (fixed_counter_disabled(idx, cpuc->pmu))
^
arch/x86/events/core.c:1760:3: warning: Using pointer that is a temporary. [danglingTemporaryLifetime]
cpuc->kfree_on_online[i] = NULL;
^
arch/x86/events/core.c:1756:31: note: Address of variable taken here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1756:39: note: Temporary created here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1760:3: note: Using pointer that is a temporary.
cpuc->kfree_on_online[i] = NULL;
^
arch/x86/events/core.c:1779:9: warning: Using pointer that is a temporary. [danglingTemporaryLifetime]
kfree(cpuc->kfree_on_online[i]);
^
arch/x86/events/core.c:1775:31: note: Address of variable taken here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1775:39: note: Temporary created here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1779:9: note: Using pointer that is a temporary.
kfree(cpuc->kfree_on_online[i]);
^
arch/x86/events/core.c:1780:3: warning: Using pointer that is a temporary. [danglingTemporaryLifetime]
cpuc->kfree_on_online[i] = NULL;
^
arch/x86/events/core.c:1775:31: note: Address of variable taken here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1775:39: note: Temporary created here.
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
^
arch/x86/events/core.c:1780:3: note: Using pointer that is a temporary.
cpuc->kfree_on_online[i] = NULL;
^
arch/x86/events/core.c:2113:3: warning: Same expression on both sides of '-'. [duplicateExpression]
__EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_counters) - 1,
^
arch/x86/events/core.c:2163:26: warning: Local variable 'hybrid_pmu' shadows outer function [shadowFunction]
struct x86_hybrid_pmu *hybrid_pmu;
^
arch/x86/events/perf_event.h:660:47: note: Shadowed declaration
static __always_inline struct x86_hybrid_pmu *hybrid_pmu(struct pmu *pmu)
^
arch/x86/events/core.c:2163:26: note: Shadow variable
struct x86_hybrid_pmu *hybrid_pmu;
^

vim +/pmu +1869 arch/x86/events/core.c

1862
1863 ssize_t events_hybrid_sysfs_show(struct device *dev,
1864 struct device_attribute *attr,
1865 char *page)
1866 {
1867 struct perf_pmu_events_hybrid_attr *pmu_attr =
1868 container_of(attr, struct perf_pmu_events_hybrid_attr, attr);
> 1869 struct x86_hybrid_pmu *pmu;
1870 const char *str, *next_str;
1871 int i;
1872
1873 if (hweight64(pmu_attr->pmu_type) == 1)
1874 return sprintf(page, "%s", pmu_attr->event_str);
1875
1876 /*
1877 * Hybrid PMUs may support the same event name, but with different
1878 * event encoding, e.g., the mem-loads event on an Atom PMU has
1879 * different event encoding from a Core PMU.
1880 *
1881 * The event_str includes all event encodings. Each event encoding
1882 * is divided by ";". The order of the event encodings must follow
1883 * the order of the hybrid PMU index.
1884 */
1885 pmu = container_of(dev_get_drvdata(dev), struct x86_hybrid_pmu, pmu);
1886
1887 str = pmu_attr->event_str;
1888 for (i = 0; i < x86_pmu.num_hybrid_pmus; i++) {
1889 if (!(x86_pmu.hybrid_pmu[i].cpu_type & pmu_attr->pmu_type))
1890 continue;
1891 if (x86_pmu.hybrid_pmu[i].cpu_type & pmu->cpu_type) {
1892 next_str = strchr(str, ';');
1893 if (next_str)
1894 return snprintf(page, next_str - str + 1, "%s", str);
1895 else
1896 return sprintf(page, "%s", str);
1897 }
1898 str = strchr(str, ';');
1899 str++;
1900 }
1901
1902 return 0;
1903 }
1904 EXPORT_SYMBOL_GPL(events_hybrid_sysfs_show);
1905

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