Re: [PATCH 03/16] mm: check rb_subtree

To:	Sasha Levin <levinsasha928@gmail.com>
Subject:	Re: [PATCH 03/16] mm: check rb_subtree_gap correctness
From:	Michel Lespinasse <walken@google.com>
Date:	Mon, 12 Nov 2012 03:55:16 -0800
Cc:	Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Hugh Dickins <hughd@google.com>, linux-kernel@vger.kernel.org, Russell King <linux@arm.linux.org.uk>, Ralf Baechle <ralf@linux-mips.org>, Paul Mundt <lethal@linux-sh.org>, "David S. Miller" <davem@davemloft.net>, Chris Metcalf <cmetcalf@tilera.com>, x86@kernel.org, William Irwin <wli@holomorphy.com>, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, Dave Jones <davej@redhat.com>
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On Fri, Nov 9, 2012 at 6:13 AM, Sasha Levin <levinsasha928@gmail.com> wrote:
> While fuzzing with trinity inside a KVM tools (lkvm) guest, using today's 
> -next
> kernel, I'm getting these:
>
> [  117.007714] free gap 7fba0dd1c000, correct 7fba0dcfb000
> [  117.019773] map_count 750 rb -1
> [  117.028362] ------------[ cut here ]------------
> [  117.029813] kernel BUG at mm/mmap.c:439!
>
> Note that they are very easy to reproduce.

Thanks for the report. I had trouble reproducing this on Friday, but
after Hugh came up with an easy test case I think I have it figured
out. I sent out a proposed fix as "[PATCH 0/3] fix missing
rb_subtree_gap updates on vma insert/erase". Let's follow up the
discussion there if necessary.

Cheers,

-- 
Michel "Walken" Lespinasse
A program is never fully debugged until the last user dies.

<Prev in Thread]	Current Thread	[Next in Thread>
[PATCH 00/16] mm: use augmented rbtrees for finding unmapped areas, Michel Lespinasse [PATCH 01/16] mm: add anon_vma_lock to validate_mm(), Michel Lespinasse Re: [PATCH 01/16] mm: add anon_vma_lock to validate_mm(), Rik van Riel [PATCH 02/16] mm: augment vma rbtree with rb_subtree_gap, Michel Lespinasse [PATCH 05/16] mm: vm_unmapped_area() lookup function, Michel Lespinasse [PATCH 06/16] mm: use vm_unmapped_area() on x86_64 architecture, Michel Lespinasse [PATCH 03/16] mm: check rb_subtree_gap correctness, Michel Lespinasse Re: [PATCH 03/16] mm: check rb_subtree_gap correctness, Andrew Morton Re: [PATCH 03/16] mm: check rb_subtree_gap correctness, Sasha Levin Re: [PATCH 03/16] mm: check rb_subtree_gap correctness, Hugh Dickins Re: [PATCH 03/16] mm: check rb_subtree_gap correctness, Michel Lespinasse <= [PATCH 07/16] mm: fix cache coloring on x86_64 architecture, Michel Lespinasse Re: [PATCH 07/16] mm: fix cache coloring on x86_64 architecture, Andrew Morton [PATCH 04/16] mm: rearrange vm_area_struct for fewer cache misses, Michel Lespinasse [PATCH 08/16] mm: use vm_unmapped_area() in hugetlbfs, Michel Lespinasse Re: [PATCH 08/16] mm: use vm_unmapped_area() in hugetlbfs, Rik van Riel [PATCH 09/16] mm: use vm_unmapped_area() in hugetlbfs on i386 architecture, Michel Lespinasse Re: [PATCH 09/16] mm: use vm_unmapped_area() in hugetlbfs on i386 architecture, Rik van Riel Re: [PATCH 09/16] mm: use vm_unmapped_area() in hugetlbfs on i386 architecture, Andrew Morton Re: [PATCH 09/16] mm: use vm_unmapped_area() in hugetlbfs on i386 architecture, Rik van Riel [PATCH 10/16] mm: use vm_unmapped_area() on mips architecture, Michel Lespinasse

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Re: [PATCH 03/16] mm: check rb_subtree_gap correctness