linux-kernel - Re: [PATCH 4/4] mm: kfence: Only load kfence

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Message-ID: <99daf260-76af-8316-fa9a-a649c8a8d1ab@huawei.com>
Date:   Wed, 25 Aug 2021 17:55:01 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Alexander Potapenko <glider@...gle.com>
CC:     Russell King <linux@...linux.org.uk>,
        Marco Elver <elver@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        kasan-dev <kasan-dev@...glegroups.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 4/4] mm: kfence: Only load kfence_test when kfence is
 enabled


On 2021/8/25 17:31, Alexander Potapenko wrote:
> On Wed, Aug 25, 2021 at 11:17 AM Kefeng Wang <wangkefeng.wang@...wei.com> wrote:
>> Provide kfence_is_enabled() helper, only load kfence_test module
>> when kfence is enabled.
> What's wrong with the current behavior?
> I think we need at least some way to tell the developer that KFENCE
> does not work, and a failing test seems to be the perfect one.

If the kfence is not enabled, eg kfence.sample_interval=0, kfence_test 
spend too much time,

and all tests will fails. It is meaningless. so better to just skip it ;)

>> diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
>> index eb6307c199ea..4087f9f1497e 100644
>> --- a/mm/kfence/kfence_test.c
>> +++ b/mm/kfence/kfence_test.c
>> @@ -847,6 +847,8 @@ static void unregister_tracepoints(struct tracepoint *tp, void *ignore)
>>    */
>>   static int __init kfence_test_init(void)
>>   {
>> +       if (!kfence_is_enabled())

Add a print info here?

>> +               return 0;
>>          /*
>>           * Because we want to be able to build the test as a module, we need to
>>           * iterate through all known tracepoints, since the static registration
>> --
>> 2.26.2
>>
>> --
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>
>