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Subject: Re: Reading `/sys/kernel/debug/kmemleak` takes 3 s and content not
 shown
To:     Christophe Leroy <christophe.leroy@c-s.fr>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
References: <88e651e2-d876-376e-81fa-eab0729ebb47@molgen.mpg.de>
 <f18fb509-bee1-e411-3761-bd28a0d8aab7@molgen.mpg.de>
 <ad2278fd-ea56-d715-7efb-c4e0adb7314e@c-s.fr>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
Message-ID: <33ad8e80-4275-d5bf-9b6a-052dd8afe7ef@molgen.mpg.de>
Date:   Tue, 26 Mar 2019 14:17:01 +0100
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Dear Christophe,


On 26.03.19 13:55, Christophe Leroy wrote:

> Le 26/03/2019 à 13:49, Paul Menzel a écrit :

>> On 19.02.19 10:44, Paul Menzel wrote:
>>
>>> On a the IBM S822LC (8335-GTA) with Ubuntu 18.10, and Linux 5.0-rc5+
>>> accessing `/sys/kernel/debug/kmemleak` takes a long time. According to
>>> strace it takes three seconds.
>>>
>>> $ dmesg | grep leak
>>> [    4.407957] kmemleak: Kernel memory leak detector initialized
>>> [    4.407959] kmemleak: Automatic memory scanning thread started
>>> [745989.625624] kmemleak: 1 new suspected memory leaks (see 
>>> /sys/kernel/debug/kmemleak)
>>> [1002619.951902] kmemleak: 1 new suspected memory leaks (see 
>>> /sys/kernel/debug/kmemleak)
>>> ```
>>>
>>> Unfortunately, the leaks supposedly stored in that file are not shown
>>> either.
>>
>> The problem is still present with Linux 5.0. Do you have an idea, how 
>> to fix this?
> 
> Have you identified a previous version that works properly?

It seems to have worked with Linux 4.18-rc4+ [1].

> If so, have you been able to bisect the problem?

No, sorry, I have not. I do not have resources for this.


Kind regards,

Paul


[1]: https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-July/175658.html