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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 6 Mar 2018 15:55:00 +0100
Message-ID: <CAK8P3a267Kj5i-DE6yx2yC=pkFKYHdU-AJo3FDE-EOgCKmOe7g@mail.gmail.com>
Subject: Re: [PATCH 4.4 163/193] kasan: rework Kconfig settings
To:     Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc:     Ben Hutchings <ben.hutchings@codethink.co.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        stable <stable@vger.kernel.org>
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On Tue, Mar 6, 2018 at 3:33 PM, Andrey Ryabinin <aryabinin@virtuozzo.com> wrote:
>
>
> On 03/06/2018 05:29 PM, Ben Hutchings wrote:
>> On Fri, 2018-02-23 at 19:26 +0100, Greg Kroah-Hartman wrote:
>>> 4.4-stable review patch.  If anyone has any objections, please let me know.
>>>
>>> ------------------
>>>
>>> From: Arnd Bergmann <arnd@arndb.de>
>>>
>>> commit e7c52b84fb18f08ce49b6067ae6285aca79084a8 upstream.
>> [...]
>>> --- a/lib/Kconfig.debug
>>> +++ b/lib/Kconfig.debug
>>> @@ -197,7 +197,7 @@ config ENABLE_MUST_CHECK
>>>  config FRAME_WARN
>>>      int "Warn for stack frames larger than (needs gcc 4.4)"
>>>      range 0 8192
>>> -    default 0 if KASAN
>>> +    default 2048 if GCC_PLUGIN_LATENT_ENTROPY
>>>      default 1024 if !64BIT
>>>      default 2048 if 64BIT
>>>      help
>>
>> This doesn't make sense for 4.4.  There is no GCC_PLUGIN_LATENT_ENTROPY
>> in 4.4, and this line wasn't added by the upstream commit.
>>
>> I think all that was really needed in the backport was to delete the
>> 'default 0', right?
>>
>
> Yep, 'default 0 if KASAN' to be precise.

Right. I sent the correct fix for v4.9, but it must have gotten mangled
during my backport to v4.4. There difference is harmless, as the
extraneous line has no effect on v4.4, but if one of you thinks I
should send a patch to remove that line for consistency, I'll gladly
do that.

        Arnd