linux-kernel - Re: [PATCH 5/6] kconfig: Don't leak help strings during parsing

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Message-ID: <CAFkk2KR7SndoEGbNvtDGjx71fNkoia7_HEYuHoaQL75Ukp9vmQ@mail.gmail.com>
Date:   Fri, 12 Jan 2018 09:47:38 +0100
From:   Ulf Magnusson <ulfalizer@...il.com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     "Yann E. MORIN" <yann.morin.1998@...e.fr>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Sam Ravnborg <sam@...nborg.org>, zippel@...ux-m68k.org,
        Nicolas Pitre <nicolas.pitre@...aro.org>,
        Michal Marek <michal.lkml@...kovi.net>, dirk@...ders.net,
        Arnaud Lacombe <lacombar@...il.com>, walch.martin@....de,
        Jan Beulich <JBeulich@...e.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/6] kconfig: Don't leak help strings during parsing

On Wed, Jan 10, 2018 at 5:12 PM, Masahiro Yamada
<yamada.masahiro@...ionext.com> wrote:
> 2017-10-09 2:11 GMT+09:00 Ulf Magnusson <ulfalizer@...il.com>:
>> This is just for completeness to get rid of the last memory leak
>> currently generated during parsing for ARCH=x86. The symbol
>> DVB_NETUP_UNIDVB in drivers/media/pci/netup_unidvb/Kconfig currently has
>> two help strings, and we leak the first one.
>
> Looks like it was fixed by
> 561b29e4ec8d0aac7e094f70d649ee4abccdda03
>
>
>
>> Summary from Valgrind on 'menuconfig' (ARCH=x86) before the fix:
>>
>>         LEAK SUMMARY:
>>            definitely lost: 344,440 bytes in 14,350 blocks
>>            ...
>>
>> Summary after the fix:
>>
>>         LEAK SUMMARY:
>>            definitely lost: 344,376 bytes in 14,349 blocks
>>            ...
>>
>> Signed-off-by: Ulf Magnusson <ulfalizer@...il.com>
>> ---
>>  scripts/kconfig/zconf.y | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/scripts/kconfig/zconf.y b/scripts/kconfig/zconf.y
>> index 468ab03..3c9f436 100644
>> --- a/scripts/kconfig/zconf.y
>> +++ b/scripts/kconfig/zconf.y
>> @@ -435,6 +435,9 @@ help_start: T_HELP T_EOL
>>
>>  help: help_start T_HELPTEXT
>>  {
>> +       if (current_entry->help)
>> +               /* Weird menu node with two help strings */
>> +               free(current_entry->help);
>>         current_entry->help = $2;
>>  };
>
>
> I applied this, but maybe is it better to warning message?
>          zconfprint("warning: ...")  or zconf_error()?
>
>
> If you send v2, I will replace this.

Yeah, that's a good idea.

New version at https://marc.info/?l=linux-kernel&m=151573969713437&w=2.
The warning seems more important than the leak, so I rephrased it a
bit.

Cheers,
Ulf