From: Andrey Ryabinin <ryabinin.a.a@gmail.com>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: Hugh Dickins <hughd@google.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Mel Gorman <mgorman@suse.de>,
Andrey Ryabinin <a.ryabinin@samsung.com>
Subject: Re: mm: NULL ptr deref in migrate_page_move_mapping
Date: Sat, 27 Sep 2014 11:01:54 +0400 [thread overview]
Message-ID: <CAPAsAGyjq1YbvYneUe3GiYhfXy0bj1VjJehbN1Kkm70B=Y_wDQ@mail.gmail.com> (raw)
In-Reply-To: <542628C8.8030004@oracle.com>
2014-09-27 7:02 GMT+04:00 Sasha Levin <sasha.levin@oracle.com>:
> On 09/22/2014 07:04 PM, Hugh Dickins wrote:
>>> but I'm not sure what went wrong.
>> Most likely would be a zeroing of the radix_tree node, just as you
>> were experiencing zeroing of other mm structures in earlier weeks.
>>
>> Not that I've got any suggestions on where to take it from there.
>
> I've added poisoning to a few mm related structures, and managed to
> confirm that the issue here is indeed corruption rather than something
> specific with the given structures.
>
> Right now I'm looking into making KASan (Cc Andrey) to mark the poison
> bytes somehow so it would trigger an error on access, that way we'll
> know what's corruption them.
>
> Andrey, since it takes a while to trigger this corruption, could you
> confirm that if I kasan_poison_shadow() a few bytes I will get a KASan
> report on any read/write to them?
>
That's right. Note that poison value has to be negative.
Address and size of poisoned area has to be aligned to 8 bytes.
--
Best regards,
Andrey Ryabinin
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prev parent reply other threads:[~2014-09-27 7:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-22 15:30 Sasha Levin
2014-09-22 23:04 ` Hugh Dickins
2014-09-22 23:49 ` Sasha Levin
2014-09-27 3:02 ` Sasha Levin
2014-09-27 7:01 ` Andrey Ryabinin [this message]
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