From: Sasha Levin <levinsasha928@gmail.com>
To: Michel Lespinasse <walken@google.com>
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>
Subject: Re: [PATCH 03/16] mm: check rb_subtree_gap correctness
Date: Fri, 09 Nov 2012 09:13:26 -0500 [thread overview]
Message-ID: <509D0F86.30607@gmail.com> (raw)
In-Reply-To: <1352155633-8648-4-git-send-email-walken@google.com>
On 11/05/2012 05:47 PM, Michel Lespinasse wrote:
> When CONFIG_DEBUG_VM_RB is enabled, check that rb_subtree_gap is
> correctly set for every vma and that mm->highest_vm_end is also correct.
>
> Also add an explicit 'bug' variable to track if browse_rb() detected any
> invalid condition.
>
> Signed-off-by: Michel Lespinasse <walken@google.com>
> Reviewed-by: Rik van Riel <riel@redhat.com>
>
> ---
Hi all,
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!
[ 117.031024] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 117.032933] Dumping ftrace buffer:
[ 117.033972] (ftrace buffer empty)
[ 117.035085] CPU 4
[ 117.035676] Pid: 6859, comm: trinity-child46 Tainted: G W 3.7.0-rc4-next-20121109-sasha-00013-g9407f3c #124
[ 117.038217] RIP: 0010:[<ffffffff81236687>] [<ffffffff81236687>] validate_mm+0x297/0x2c0
[ 117.041056] RSP: 0018:ffff880016a4fdf8 EFLAGS: 00010296
[ 117.041056] RAX: 0000000000000013 RBX: 00000000ffffffff RCX: 0000000000000006
[ 117.041056] RDX: 0000000000005270 RSI: ffff880024120910 RDI: 0000000000000286
[ 117.052131] RBP: ffff880016a4fe48 R08: 0000000000000000 R09: 0000000000000000
[ 117.052131] R10: 0000000000000001 R11: 0000000000000000 R12: 00000000000002ee
[ 117.052131] R13: 00007fffea1fc000 R14: ffff88002412c000 R15: 0000000000000000
[ 117.052131] FS: 00007fba129db700(0000) GS:ffff880063600000(0000) knlGS:0000000000000000
[ 117.052131] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 117.052131] CR2: 0000000003323288 CR3: 00000000169b2000 CR4: 00000000000406e0
[ 117.052131] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 117.052131] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 117.052131] Process trinity-child46 (pid: 6859, threadinfo ffff880016a4e000, task ffff880024120000)
[ 117.052131] Stack:
[ 117.052131] ffffffff8489e201 ffffffff81235aa0 ffff88000885cac8 0000000100000000
[ 117.052131] ffffffff812361b9 ffff88002412c000 ffff88000885cac8 ffff88000885cdc8
[ 117.052131] ffff88000885cdd0 ffff88002412c000 ffff880016a4fe98 ffffffff812367b4
[ 117.052131] Call Trace:
[ 117.052131] [<ffffffff81235aa0>] ? vma_compute_subtree_gap+0x40/0x40
[ 117.052131] [<ffffffff812361b9>] ? vma_gap_update+0x19/0x30
[ 117.052131] [<ffffffff812367b4>] vma_link+0x94/0xe0
[ 117.052131] [<ffffffff812386c4>] do_brk+0x2c4/0x380
[ 117.052131] [<ffffffff812387bf>] ? sys_brk+0x3f/0x190
[ 117.052131] [<ffffffff812388ce>] sys_brk+0x14e/0x190
[ 117.052131] [<ffffffff83be2618>] tracesys+0xe1/0xe6
[ 117.052131] Code: d8 41 8b 76 60 39 de 74 1b 89 da 48 c7 c7 c6 d9 89 84 31 c0 e8 01 76 94 02 eb 10 66 0f 1f 84 00 00 00 00 00
8b 45 c8 85 c0 74 18 <0f> 0b 4c 8d 48 e0 48 8b 70 e0 31 db c7 45 cc 00 00 00 00 e9 f4
[ 117.052131] RIP [<ffffffff81236687>] validate_mm+0x297/0x2c0
[ 117.052131] RSP <ffff880016a4fdf8>
[ 117.136092] ---[ end trace 5ce250e0bf6d040c ]---
Note that they are very easy to reproduce.
Also, I see that lots of the code there has a local variable named 'bug' thats tracking
whether we should BUG() later on. Why does it work that way and the BUG() isn't immediate?
Thanks,
Sasha
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next prev parent reply other threads:[~2012-11-09 14:13 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-05 22:46 [PATCH 00/16] mm: use augmented rbtrees for finding unmapped areas Michel Lespinasse
2012-11-05 22:46 ` [PATCH 01/16] mm: add anon_vma_lock to validate_mm() Michel Lespinasse
2012-11-05 23:06 ` Rik van Riel
2012-11-06 8:00 ` Michel Lespinasse
2012-11-05 22:46 ` [PATCH 02/16] mm: augment vma rbtree with rb_subtree_gap Michel Lespinasse
2012-11-05 22:47 ` [PATCH 03/16] mm: check rb_subtree_gap correctness Michel Lespinasse
2012-11-06 22:38 ` Andrew Morton
2012-11-09 14:13 ` Sasha Levin [this message]
2012-11-09 20:06 ` Hugh Dickins
2012-11-12 11:55 ` Michel Lespinasse
2012-11-05 22:47 ` [PATCH 04/16] mm: rearrange vm_area_struct for fewer cache misses Michel Lespinasse
2012-11-05 22:47 ` [PATCH 05/16] mm: vm_unmapped_area() lookup function Michel Lespinasse
2012-11-05 22:47 ` [PATCH 06/16] mm: use vm_unmapped_area() on x86_64 architecture Michel Lespinasse
2012-11-05 22:47 ` [PATCH 07/16] mm: fix cache coloring " Michel Lespinasse
2012-11-06 22:38 ` Andrew Morton
2012-11-05 22:47 ` [PATCH 08/16] mm: use vm_unmapped_area() in hugetlbfs Michel Lespinasse
2012-11-05 23:33 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 09/16] mm: use vm_unmapped_area() in hugetlbfs on i386 architecture Michel Lespinasse
2012-11-05 23:07 ` Rik van Riel
2012-11-06 22:38 ` Andrew Morton
2012-11-06 22:48 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 10/16] mm: use vm_unmapped_area() on mips architecture Michel Lespinasse
2012-11-05 23:34 ` Rik van Riel
2012-11-06 22:38 ` Andrew Morton
2012-11-05 22:47 ` [PATCH 11/16] mm: use vm_unmapped_area() on arm architecture Michel Lespinasse
2012-11-05 23:35 ` Rik van Riel
2012-11-06 22:38 ` Andrew Morton
2012-11-05 22:47 ` [PATCH 12/16] mm: use vm_unmapped_area() on sh architecture Michel Lespinasse
2012-11-05 23:35 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 13/16] mm: use vm_unmapped_area() on sparc64 architecture Michel Lespinasse
2012-11-05 23:36 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 14/16] mm: use vm_unmapped_area() in hugetlbfs " Michel Lespinasse
2012-11-05 23:36 ` Rik van Riel
2012-11-05 22:47 ` [PATCH 15/16] mm: use vm_unmapped_area() on sparc32 architecture Michel Lespinasse
2012-11-05 23:37 ` Rik van Riel
2012-11-06 1:25 ` David Miller
2012-11-06 3:13 ` Michel Lespinasse
2012-11-06 7:30 ` Rik van Riel
2012-11-06 17:41 ` David Miller
2012-11-05 22:47 ` [PATCH 16/16] mm: use vm_unmapped_area() in hugetlbfs on tile architecture Michel Lespinasse
2012-11-05 23:37 ` Rik van Riel
2012-11-06 22:11 ` [PATCH 00/16] mm: use augmented rbtrees for finding unmapped areas Andrew Morton
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