linux-kernel - Re: [PATCH 2/6] x86,perf/cqm: Fix cqm memory leak and notifier leak

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Date:	Wed, 2 Mar 2016 09:58:37 -0800 (PST)
From:	Vikas Shivappa <vikas.shivappa@...el.com>
To:	Thomas Gleixner <tglx@...utronix.de>
cc:	Vikas Shivappa <vikas.shivappa@...ux.intel.com>,
	vikas.shivappa@...el.com, linux-kernel@...r.kernel.org,
	x86@...nel.org, hpa@...or.com, mingo@...nel.org,
	peterz@...radead.org, ravi.v.shankar@...el.com,
	tony.luck@...el.com, fenghua.yu@...el.com, h.peter.anvin@...el.com
Subject: Re: [PATCH 2/6] x86,perf/cqm: Fix cqm memory leak and notifier
 leak



On Wed, 2 Mar 2016, Thomas Gleixner wrote:

> On Tue, 1 Mar 2016, Vikas Shivappa wrote:
>
>> Fixes the hotcpu notifier leak and a memory leak during cqm(cache
>> quality of service monitoring) initialization.
>>
>> Reviewed-by: Tony Luck <tony.luck@...el.com>
>> Signed-off-by: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
>> ---
>>  arch/x86/kernel/cpu/perf_event_intel_cqm.c | 17 ++++++++++++-----
>>  1 file changed, 12 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
>> index e6be335..5666171 100644
>> --- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c
>> +++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
>> @@ -1322,7 +1322,7 @@ static const struct x86_cpu_id intel_cqm_match[] = {
>>
>>  static int __init intel_cqm_init(void)
>>  {
>> -	char *str, scale[20];
>> +	char *str = NULL, scale[20];
>>  	int i, cpu, ret;
>>
>>  	if (!x86_match_cpu(intel_cqm_match))
>> @@ -1382,16 +1382,23 @@ static int __init intel_cqm_init(void)
>>  		cqm_pick_event_reader(i);
>>  	}
>>
>> -	__perf_cpu_notifier(intel_cqm_cpu_notifier);
>> -
>>  	ret = perf_pmu_register(&intel_cqm_pmu, "intel_cqm", -1);
>> -	if (ret)
>> +	if (ret) {
>>  		pr_err("Intel CQM perf registration failed: %d\n", ret);
>> -	else
>> +		goto out;
>> +	} else {
>>  		pr_info("Intel CQM monitoring enabled\n");
>> +	}
>>
>> +	/*
>> +	 * Register the hot cpu notifier once we are sure cqm
>> +	 * is enabled to avoid notifier leak.
>> +	 */
>> +	__perf_cpu_notifier(intel_cqm_cpu_notifier);
>>  out:
>>  	cpu_notifier_register_done();
>> +	if (ret)
>> +		kfree(str);
>
> This still leaks cqm_rmid_ptrs ....
>

Thats right. Thought there must be something more than the str leak i fixed, 
but missed this. Will fix

Thanks,
Vikas