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Date: Wed, 12 Aug 2015 14:27:34 +0200
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: mm: use after free and panic in free_pages_and_swap_cache
Message-ID: <20150812122734.GB5182@dhcp22.suse.cz>
References: <55C8A902.4080207@oracle.com>
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To: Sasha Levin <sasha.levin@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, Johannes Weiner <hannes@cmpxchg.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>

On Mon 10-08-15 09:37:06, Sasha Levin wrote:
> Hi all,

Hi Sasha,

> While fuzzing with trinity inside a KVM tools guest running -next I've
> stumbled on the following:

Could post your config somewhere please? Or maybe just the disassemble
of free_pages_and_swap_cache and tlb_flush_mmu_free should be sufficient.

I am not sure I read the report properly. It all seem to point to
free_pages_and_swap_cache resp. tlb_flush_mmu_free but I fail to see
what could be wrong there.  The last reference on the page should be
dropped in release_pages.  The given pages array shouldn't be freed
behind our back as well because mmu_gather is local to this path.

-- 
Michal Hocko
SUSE Labs

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