[PATCH 4.8 04/96] perf/x86/intel/cstate: Prevent hotplug callback leak

From: Greg Kroah-Hartman
Date: Fri Jan 06 2017 - 16:50:30 EST


4.8-stable review patch. If anyone has any objections, please let me know.

------------------

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

commit 834fcd298003c10ce450e66960c78893cb1cc4b5 upstream.

If the pmu registration fails the registered hotplug callbacks are not
removed. Wrong in any case, but fatal in case of a modular driver.

Replace the nonsensical state names with proper ones while at it.

Fixes: 77c34ef1c319 ("perf/x86/intel/cstate: Convert Intel CSTATE to hotplug state machine")
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Sebastian Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/events/intel/cstate.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

--- a/arch/x86/events/intel/cstate.c
+++ b/arch/x86/events/intel/cstate.c
@@ -571,6 +571,9 @@ static int __init cstate_probe(const str

static inline void cstate_cleanup(void)
{
+ cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_CSTATE_ONLINE);
+ cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_CSTATE_STARTING);
+
if (has_cstate_core)
perf_pmu_unregister(&cstate_core_pmu);

@@ -583,16 +586,16 @@ static int __init cstate_init(void)
int err;

cpuhp_setup_state(CPUHP_AP_PERF_X86_CSTATE_STARTING,
- "AP_PERF_X86_CSTATE_STARTING", cstate_cpu_init,
- NULL);
+ "perf/x86/cstate:starting", cstate_cpu_init, NULL);
cpuhp_setup_state(CPUHP_AP_PERF_X86_CSTATE_ONLINE,
- "AP_PERF_X86_CSTATE_ONLINE", NULL, cstate_cpu_exit);
+ "perf/x86/cstate:online", NULL, cstate_cpu_exit);

if (has_cstate_core) {
err = perf_pmu_register(&cstate_core_pmu, cstate_core_pmu.name, -1);
if (err) {
has_cstate_core = false;
pr_info("Failed to register cstate core pmu\n");
+ cstate_cleanup();
return err;
}
}
@@ -606,8 +609,7 @@ static int __init cstate_init(void)
return err;
}
}
-
- return err;
+ return 0;
}

static int __init cstate_pmu_init(void)
@@ -632,8 +634,6 @@ module_init(cstate_pmu_init);

static void __exit cstate_pmu_exit(void)
{
- cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_CSTATE_ONLINE);
- cpuhp_remove_state_nocalls(CPUHP_AP_PERF_X86_CSTATE_STARTING);
cstate_cleanup();
}
module_exit(cstate_pmu_exit);