From: Alexey Izbyshev <izbyshev@ispras.ru>
To: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Dmitry Safonov <dsafonov@virtuozzo.com>,
Thomas Gleixner <tglx@linutronix.de>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Borislav Petkov <bp@suse.de>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Alexander Monakov <amonakov@ispras.ru>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [4.11 Regression] 64-bit process gets AT_BASE in the first 4 GB if exec'ed from 32-bit process
Date: Fri, 18 May 2018 00:19:13 +0300 [thread overview]
Message-ID: <b521abc931607d0af8f7d42775dce47d@ispras.ru> (raw)
In-Reply-To: <CAJwJo6Zad1S_Ontm3-oUjrtxdsz+sTfgufCcskpYfik=pOxd=g@mail.gmail.com>
On 2018-05-18 00:11, Dmitry Safonov wrote:
> 2018-05-17 22:07 GMT+01:00 Andy Lutomirski <luto@kernel.org>:
>> On Thu, May 17, 2018 at 1:51 PM Dmitry Safonov <0x7f454c46@gmail.com>
>> wrote:
>>
>>> 2018-05-17 21:46 GMT+01:00 Andy Lutomirski <luto@kernel.org>:
>>> > On Thu, May 17, 2018 at 1:25 PM Alexey Izbyshev <izbyshev@ispras.ru>
>> wrote:
>>> >
>>> >> Hello everyone,
>>> >
>>> >> I've discovered the following strange behavior of a 4.15.13-based
>> kernel
>>> >> (bisected to
>>> >
>>> >
>>> >
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1b028f784e8c341e762c264f70dc0ca1418c8b7a
>>> >> between 4.11-rc2 and -rc3 thanks to Alexander Monakov).
>>> >
>>> >
>>> > It's definitely not intended. Can you confirm that the problem still
>>> > exists in 4.16? I have some vague recollection that this was a known
>> issue
>>> > that got fixed, and we could plausibly just be missing a backport.
>>
>>> I'm looking into that ATM, the problem like that was fixed with
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ada26481dfe6
>>
>>> Will check what's happening there.
>>
>> I haven't tried to figure out exactly what code calls which function,
>> but
>> it seems like set_personality_64bit() really ought to clear TS_COMPAT.
>
> Ugh, yeah, the same way __set_personality_x32().
> Will test it and prepare a patch for that Cc'ing stable.
>
> Thanks, Alexey, Andy!
>
Thanks, Dmitry, Andy for the quick investigation, and Alexander for the
confirmation!
-Alexey
next prev parent reply other threads:[~2018-05-17 21:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-17 20:16 Alexey Izbyshev
2018-05-17 20:46 ` Andy Lutomirski
2018-05-17 20:50 ` Dmitry Safonov
2018-05-17 21:07 ` Andy Lutomirski
2018-05-17 21:11 ` Dmitry Safonov
2018-05-17 21:19 ` Alexey Izbyshev [this message]
2018-05-17 20:53 ` Alexander Monakov
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