From: Linus Torvalds <torvalds@linux-foundation.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>,
Minchan Kim <minchan.kim@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Lee Schermerhorn <Lee.Schermerhorn@hp.com>,
Nick Piggin <npiggin@suse.de>,
Andrea Arcangeli <aarcange@redhat.com>,
Hugh Dickins <hugh.dickins@tiscali.co.uk>,
sgunderson@bigfoot.com
Subject: Re: Ugly rmap NULL ptr deref oopsie on hibernate (was Linux 2.6.34-rc3)
Date: Tue, 6 Apr 2010 14:27:37 -0700 (PDT) [thread overview]
Message-ID: <alpine.LFD.2.00.1004061403170.3487@i5.linux-foundation.org> (raw)
In-Reply-To: <20100406205123.GC20357@a1.tnic>
On Tue, 6 Apr 2010, Borislav Petkov wrote:
> > So again, it's actually anon_vma.head.next that is NULL, not any of the
> > entries on the list itself.
> >
> > Now, I can see several cases for this:
> >
> > - the obvious one: anon_vma just wasn't correctly initialized, and is
> > missing a INIT_LIST_HEAD(&anon_vma->head). That's either a slab bug (we
> > don't have a whole lot of coverage of constructors), or somebody
> > allocated an anon_vma without using the anon_vma_cachep.
>
> I've added code to verify this and am suspend/resuming now... Wait a
> minute, Linus, you're good! :) :
>
> [ 873.083074] PM: Preallocating image memory...
> [ 873.254359] NULL anon_vma->head.next, page 2182681
Yeah, I was pretty sure of that thing.
I still don't see _how_ it happens, though. That 'struct anon_vma' is very
simple, and contains literally just the lock and that list_head.
Now, 'head.next' is kind of magical, because it contains that magic
low-bit "have I been locked" thing (see "vm_lock_anon_vma()" in
mm/mmap.c). But I'm not seeing anything else touching it.
And if you allocate a anon_vma the proper way, the SLUB constructor should
have made sure that the head is initialized. And no normal list operation
ever sets any list pointer to zero, although a "list_del()" on the first
list entry could do it if that first list entry had a NULL next pointer.
> Now, how do we track back to the place which is missing anon_vma->head
> init? Can we use the struct page *page arg to page_referenced_anon()
> somehow?
You might enable SLUB debugging (both SLUB_DEBUG _and_ SLUB_DEBUG_ON), and
then make the "object_err()" function in mm/slub.c be non-static. You
could call it when you see the problem, perhaps.
Or you could just add tests to both alloc_anon_vma() and free_anon_vma()
to check that 'list_empty(&anon_vma->head)' is true. I dunno.
> > I haven't looked at the kernel config files: do they perhaps share the
> > same (odd?) SLUB/SLAB/SLOB config?
>
> what is an odd SL[AOU]B config?
Probably anything but the default SLUB these days. But Steinar already
said he had SLUB, so it's unlikely to be something odd.
> > - anon_vma isn't actually an anonvma at all. 'page->mapping' was crud
> > with the low bit set. That sounds unlikely, but who knows. The ksm code
> > sets mapping to "stable_node + PAGE_MAPPING_ANON | PAGE_MAPPING_KSM"
> >
> > Did people have KSM enabled?
>
> Nope, KSM is off here.
Yeah, wasn't for Steinar either. So it doesn't look like it's any odd
corner case that depends on some odd configuration.
Linus
next prev parent reply other threads:[~2010-04-06 21:32 UTC|newest]
Thread overview: 231+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-30 17:50 Linux 2.6.34-rc3 Linus Torvalds
2010-03-30 21:16 ` [Regression, post-rc2] Commit a5ee4eb7541 breaks OpenGL on RS780 (was: Re: Linux 2.6.34-rc3) Rafael J. Wysocki
2010-03-31 20:34 ` [stable] " Greg KH
2010-04-01 1:13 ` Rafael J. Wysocki
2010-04-01 2:19 ` Alex Deucher
2010-04-01 6:36 ` Clemens Ladisch
2010-04-01 15:01 ` Alex Deucher
2010-04-01 20:28 ` Rafael J. Wysocki
2010-04-01 20:39 ` Alex Deucher
2010-04-01 20:48 ` Rafael J. Wysocki
2010-04-01 21:00 ` Alex Deucher
2010-04-01 21:01 ` Alex Deucher
2010-04-01 21:08 ` Rafael J. Wysocki
2010-04-01 21:13 ` Alex Deucher
2010-04-01 21:46 ` Rafael J. Wysocki
2010-04-01 22:07 ` Alex Deucher
2010-04-01 23:20 ` Rafael J. Wysocki
2010-04-02 0:23 ` Linus Torvalds
2010-04-02 16:46 ` Rafael J. Wysocki
2010-04-03 18:08 ` Clemens Ladisch
2010-04-03 19:33 ` Rafael J. Wysocki
2010-04-01 16:29 ` Linus Torvalds
2010-04-01 17:07 ` Alex Deucher
2010-04-01 17:24 ` Linus Torvalds
2010-04-01 17:50 ` [Regression, post-rc2] Commit a5ee4eb7541 breaks OpenGL on RS780 Clemens Ladisch
2010-04-01 17:53 ` [Regression, post-rc2] Commit a5ee4eb7541 breaks OpenGL on RS780 (was: Re: Linux 2.6.34-rc3) Alex Deucher
2010-04-01 20:17 ` Linus Torvalds
2010-04-01 20:23 ` Alex Deucher
2010-04-01 19:46 ` Rafael J. Wysocki
2010-04-01 22:48 ` Jesse Barnes
2010-04-01 23:23 ` Rafael J. Wysocki
2010-04-02 17:59 ` Ugly rmap NULL ptr deref oopsie on hibernate (was " Borislav Petkov
2010-04-02 18:09 ` Linus Torvalds
2010-04-02 15:24 ` Andrew Morton
2010-04-02 18:37 ` Linus Torvalds
2010-04-02 22:01 ` Rik van Riel
2010-04-03 0:19 ` Linus Torvalds
2010-04-04 16:12 ` Minchan Kim
2010-04-04 17:24 ` Rik van Riel
2010-04-04 23:09 ` [PATCH] rmap: fix anon_vma_fork() memory leak Rik van Riel
2010-04-04 23:56 ` Minchan Kim
2010-04-05 15:37 ` Linus Torvalds
2010-04-05 15:48 ` Minchan Kim
2010-04-05 16:04 ` Rik van Riel
2010-04-05 16:13 ` [PATCH -v2] " Rik van Riel
2010-04-06 8:53 ` Ugly rmap NULL ptr deref oopsie on hibernate (was Linux 2.6.34-rc3) KOSAKI Motohiro
2010-04-06 10:09 ` KOSAKI Motohiro
2010-04-06 14:34 ` Rik van Riel
2010-04-06 14:38 ` Rik van Riel
2010-04-06 15:34 ` Minchan Kim
2010-04-06 15:40 ` Rik van Riel
2010-04-06 15:58 ` Minchan Kim
2010-04-06 15:55 ` Linus Torvalds
2010-04-06 16:23 ` Minchan Kim
2010-04-06 16:28 ` Linus Torvalds
2010-04-06 16:45 ` Minchan Kim
2010-04-06 16:53 ` Linus Torvalds
2010-04-06 17:04 ` Rik van Riel
2010-04-06 18:28 ` Linus Torvalds
2010-04-06 19:03 ` Andrew Morton
2010-04-06 19:10 ` Steinar H. Gunderson
2010-04-06 19:10 ` Linus Torvalds
2010-04-06 19:35 ` Linus Torvalds
2010-04-06 19:42 ` Borislav Petkov
2010-04-06 20:02 ` Linus Torvalds
2010-04-06 20:46 ` Steinar H. Gunderson
2010-04-06 20:56 ` Linus Torvalds
2010-04-06 21:05 ` Steinar H. Gunderson
2010-04-06 20:51 ` Borislav Petkov
2010-04-06 21:27 ` Linus Torvalds [this message]
2010-04-06 22:59 ` Borislav Petkov
2010-04-06 23:27 ` Linus Torvalds
2010-04-06 23:54 ` [PATCH] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA Rik van Riel
2010-04-07 7:00 ` KOSAKI Motohiro
2010-04-07 14:48 ` Rik van Riel
2010-04-07 14:54 ` [PATCH -v2] " Rik van Riel
2010-04-07 15:30 ` Linus Torvalds
2010-04-07 15:52 ` Rik van Riel
2010-04-07 16:56 ` Linus Torvalds
2010-04-07 21:19 ` Linus Torvalds
2010-04-07 21:52 ` Rik van Riel
2010-04-07 22:09 ` Linus Torvalds
2010-04-07 22:15 ` Linus Torvalds
2010-04-08 0:38 ` Rik van Riel
2010-04-07 23:37 ` Linus Torvalds
2010-04-08 2:03 ` KOSAKI Motohiro
2010-04-08 2:33 ` Linus Torvalds
2010-04-08 5:47 ` Borislav Petkov
2010-04-08 14:11 ` Linus Torvalds
2010-04-08 18:25 ` Rik van Riel
2010-04-08 18:32 ` Linus Torvalds
2010-04-08 20:31 ` Borislav Petkov
2010-04-08 21:00 ` Borislav Petkov
2010-04-08 23:16 ` Linus Torvalds
2010-04-08 23:47 ` Borislav Petkov
2010-04-09 0:50 ` Linus Torvalds
2010-04-09 1:30 ` Borislav Petkov
2010-04-09 9:21 ` Borislav Petkov
2010-04-09 16:35 ` Linus Torvalds
2010-04-09 17:40 ` Borislav Petkov
2010-04-09 17:50 ` Linus Torvalds
2010-04-09 19:14 ` Borislav Petkov
2010-04-09 19:32 ` Linus Torvalds
2010-04-09 20:03 ` Rik van Riel
2010-04-09 20:43 ` Johannes Weiner
2010-04-09 20:57 ` Rik van Riel
2010-04-09 21:33 ` Borislav Petkov
2010-04-09 23:22 ` Linus Torvalds
2010-04-09 23:45 ` Rik van Riel
2010-04-10 0:03 ` Linus Torvalds
2010-04-10 0:11 ` Rik van Riel
2010-04-09 23:54 ` Johannes Weiner
2010-04-09 23:56 ` Linus Torvalds
2010-04-10 0:19 ` Rik van Riel
2010-04-10 0:31 ` Johannes Weiner
2010-04-10 0:32 ` Linus Torvalds
2010-04-10 7:27 ` Borislav Petkov
2010-04-10 11:26 ` Borislav Petkov
2010-04-10 14:45 ` Rik van Riel
2010-04-10 15:24 ` Linus Torvalds
2010-04-10 16:38 ` Borislav Petkov
2010-04-10 17:05 ` Linus Torvalds
2010-04-10 18:21 ` Linus Torvalds
2010-04-10 18:26 ` Linus Torvalds
2010-04-10 18:51 ` Borislav Petkov
2010-04-10 18:58 ` Borislav Petkov
2010-04-10 20:05 ` Linus Torvalds
2010-04-10 20:12 ` Linus Torvalds
2010-04-10 20:36 ` Borislav Petkov
2010-04-10 20:40 ` Linus Torvalds
2010-04-10 21:25 ` Borislav Petkov
2010-04-10 21:30 ` Linus Torvalds
2010-04-10 21:51 ` Borislav Petkov
2010-04-11 13:08 ` Borislav Petkov
2010-04-11 13:19 ` [PATCH 1/3] mm: make page freeing path RCU-safe Borislav Petkov
2010-04-11 13:19 ` [PATCH 2/3] mm: cleanup find_mergeable_anon_vma complexity Borislav Petkov
2010-04-11 13:19 ` [PATCH 3/3] mm: fixup vma_adjust Borislav Petkov
2010-04-11 13:25 ` [PATCH 2/3] mm: cleanup find_mergeable_anon_vma complexity Borislav Petkov
2010-04-11 17:07 ` [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA Linus Torvalds
2010-04-11 17:16 ` Linus Torvalds
2010-04-11 18:55 ` Borislav Petkov
2010-04-12 0:13 ` Linus Torvalds
2010-04-12 1:04 ` Linus Torvalds
2010-04-12 7:20 ` Borislav Petkov
2010-04-12 16:02 ` Linus Torvalds
2010-04-12 16:26 ` Linus Torvalds
2010-04-12 18:40 ` Rik van Riel
2010-04-12 19:00 ` Borislav Petkov
2010-04-12 19:17 ` Linus Torvalds
2010-04-12 20:22 ` [PATCH 1/4] Simplify and comment on anon_vma re-use for anon_vma_prepare() Linus Torvalds
2010-04-12 20:23 ` [PATCH 2/4] vma_adjust: fix the copying of anon_vma chains Linus Torvalds
2010-04-12 20:23 ` [PATCH 3/4] anon_vma: clone the anon_vma chain in the right order Linus Torvalds
2010-04-12 20:23 ` [PATCH 4/4] anonvma: when setting up page->mapping, we need to pick the _oldest_ anonvma Linus Torvalds
2010-04-12 21:03 ` Rik van Riel
2010-04-13 0:41 ` Johannes Weiner
2010-04-13 1:08 ` Linus Torvalds
2010-04-13 4:23 ` Minchan Kim
2010-04-13 4:26 ` Minchan Kim
2010-04-12 20:57 ` [PATCH 3/4] anon_vma: clone the anon_vma chain in the right order Rik van Riel
2010-04-13 0:18 ` Johannes Weiner
2010-04-13 4:16 ` Minchan Kim
2010-04-12 20:54 ` [PATCH 2/4] vma_adjust: fix the copying of anon_vma chains Rik van Riel
2010-04-12 23:59 ` Johannes Weiner
2010-04-13 4:15 ` Minchan Kim
2010-04-12 20:54 ` [PATCH 1/4] Simplify and comment on anon_vma re-use for anon_vma_prepare() Rik van Riel
2010-04-12 23:54 ` Johannes Weiner
2010-04-13 4:04 ` Minchan Kim
2010-04-13 9:51 ` Peter Zijlstra
2010-04-12 21:50 ` [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA Borislav Petkov
2010-04-12 22:11 ` Linus Torvalds
2010-04-12 22:18 ` Linus Torvalds
2010-04-12 22:29 ` Borislav Petkov
2010-04-13 9:38 ` Borislav Petkov
2010-04-14 21:59 ` [PATCH] rmap: add exclusively owned pages to the newest anon_vma Rik van Riel
2010-04-14 23:20 ` Johannes Weiner
2010-04-15 8:34 ` Borislav Petkov
2010-04-15 16:02 ` Minchan Kim
2010-04-15 20:01 ` Linus Torvalds
2010-04-16 6:09 ` Felipe Balbi
2010-04-16 14:48 ` Linus Torvalds
2010-04-11 19:49 ` [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA Rik van Riel
2010-04-12 15:44 ` Linus Torvalds
2010-04-12 15:51 ` Rik van Riel
2010-04-11 21:45 ` Rik van Riel
2010-04-12 15:51 ` Linus Torvalds
2010-04-13 10:36 ` KOSAKI Motohiro
2010-04-10 20:24 ` Rik van Riel
2010-04-10 20:34 ` Linus Torvalds
2010-04-10 20:43 ` Rik van Riel
2010-04-10 20:32 ` Rik van Riel
2010-04-10 19:36 ` Rik van Riel
2010-04-12 14:40 ` Peter Zijlstra
2010-04-12 15:17 ` Minchan Kim
2010-04-12 15:33 ` Peter Zijlstra
2010-04-12 15:19 ` Rik van Riel
2010-04-12 16:01 ` Peter Zijlstra
2010-04-12 16:06 ` Rik van Riel
2010-04-12 16:46 ` Linus Torvalds
2010-04-12 18:40 ` Peter Zijlstra
2010-04-12 19:30 ` Peter Zijlstra
2010-04-12 19:44 ` Peter Zijlstra
2010-04-13 10:53 ` KOSAKI Motohiro
2010-04-13 11:30 ` Peter Zijlstra
2010-04-13 12:00 ` KOSAKI Motohiro
2010-04-14 14:27 ` Peter Zijlstra
2010-04-10 17:07 ` Borislav Petkov
2010-04-10 16:41 ` Linus Torvalds
2010-04-10 22:49 ` Johannes Weiner
2010-04-10 23:31 ` Linus Torvalds
2010-04-09 1:45 ` KOSAKI Motohiro
2010-04-07 15:55 ` Minchan Kim
2010-04-07 7:29 ` Ugly rmap NULL ptr deref oopsie on hibernate (was Linux 2.6.34-rc3) Borislav Petkov
2010-04-07 14:05 ` Paulo Marques
2010-04-07 14:13 ` Borislav Petkov
2010-04-06 23:37 ` Linus Torvalds
2010-04-06 23:22 ` Rik van Riel
2010-04-07 0:10 ` Linus Torvalds
2010-04-07 1:18 ` Rik van Riel
2010-04-07 7:22 ` Borislav Petkov
2010-04-07 10:09 ` Pekka Enberg
2010-04-07 10:12 ` KOSAKI Motohiro
2010-04-07 8:41 ` Peter Zijlstra
2010-04-07 8:36 ` Peter Zijlstra
2010-04-07 9:16 ` Johannes Weiner
2010-04-07 9:37 ` Peter Zijlstra
2010-04-07 14:12 ` Rik van Riel
2010-04-07 15:46 ` Linus Torvalds
2010-04-06 16:32 ` Linus Torvalds
2010-04-06 16:54 ` Minchan Kim
2010-04-07 8:37 ` Peter Zijlstra
2010-04-06 17:05 ` Borislav Petkov
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