From: christophe leroy <christophe.leroy@c-s.fr>
To: bugzilla-daemon@bugzilla.kernel.org,
linuxppc-dev@lists.ozlabs.org,
Andrew Morton <akpm@linux-foundation.org>,
Linux Memory Management List <linux-mm@kvack.org>,
linux-btrfs@vger.kernel.org, erhard_f@mailbox.org,
Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [Bug 204371] BUG kmalloc-4k (Tainted: G W ): Object padding overwritten
Date: Sat, 17 Aug 2019 10:09:46 +0200 [thread overview]
Message-ID: <e8b5b450-bdb2-6be8-8b14-bd76b81de9a0@c-s.fr> (raw)
In-Reply-To: <bug-204371-206035-O9m4mwJN9f@https.bugzilla.kernel.org/>
Le 30/07/2019 à 20:52, bugzilla-daemon@bugzilla.kernel.org a écrit :
> https://bugzilla.kernel.org/show_bug.cgi?id=204371
>
> --- Comment #2 from Andrew Morton (akpm@linux-foundation.org) ---
> (switched to email. Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
Reply all replies to bugzilla-daemon@bugzilla.kernel.org only.
[...]
>
> cc'ing various people here.
Hum ... only got that email through the bugzilla interface, and CC'ed
people don't show up.
>
> I suspect proc_cgroup_show() is innocent and that perhaps
> bpf_prepare_filter() had a memory scribble. iirc there has been at
> least one recent pretty serious bpf fix applied recently. Can others
> please take a look?
>
> (Seriously - please don't modify this report via the bugzilla web interface!)
>
Haven't got the original CC'ed list, so please reply with missing Cc's
if any.
We have well progressed on this case.
Erhard made a relation being this "Object padding overwritten" issue
arising on any driver, and the presence of the BTRFS driver.
Then he was able to bisect the issue to:
commit 69d2480456d1baf027a86e530989d7bedd698d5f
Author: David Sterba <dsterba@suse.com>
Date: Fri Jun 29 10:56:44 2018 +0200
btrfs: use copy_page for copying pages instead of memcpy
Use the helper that's possibly optimized for full page copies.
Signed-off-by: David Sterba <dsterba@suse.com>
After looking in the code, it has appeared that some of the said "pages"
were allocated with "kzalloc()".
Using the patch https://patchwork.ozlabs.org/patch/1148033/ Erhard
confirmed that some btrfs functions were calling copy_page() with
misaligned destinations.
copy_page(), at least on powerpc, expects cache aligned destination.
The patch https://patchwork.ozlabs.org/patch/1148606/ fixes the issue.
Christophe
---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus
next prev parent reply other threads:[~2019-08-17 8:11 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-204371-206035@https.bugzilla.kernel.org/>
2019-07-29 23:28 ` [Bug 204371] BUG kmalloc-4k (Tainted: G W ): Object padding overwritten bugzilla-daemon
2019-07-30 18:52 ` bugzilla-daemon
2019-07-31 12:00 ` Michael Ellerman
2019-08-17 8:09 ` christophe leroy [this message]
2019-07-31 9:03 ` bugzilla-daemon
2019-07-31 12:09 ` bugzilla-daemon
2019-08-01 12:47 ` bugzilla-daemon
2019-08-06 20:47 ` bugzilla-daemon
2019-08-06 20:48 ` bugzilla-daemon
2019-08-06 20:51 ` bugzilla-daemon
2019-08-08 10:53 ` bugzilla-daemon
2019-08-08 11:26 ` bugzilla-daemon
2019-08-09 12:31 ` Michael Ellerman
2019-08-09 12:31 ` bugzilla-daemon
2019-08-11 20:03 ` bugzilla-daemon
2019-08-11 21:18 ` bugzilla-daemon
2019-08-13 9:19 ` bugzilla-daemon
2019-08-13 9:20 ` bugzilla-daemon
2019-08-13 15:38 ` bugzilla-daemon
2019-08-14 8:56 ` bugzilla-daemon
2019-08-14 15:12 ` bugzilla-daemon
2019-08-14 16:10 ` bugzilla-daemon
2019-08-14 17:44 ` bugzilla-daemon
2019-08-14 17:45 ` bugzilla-daemon
2019-08-14 17:48 ` bugzilla-daemon
2019-08-14 17:53 ` bugzilla-daemon
2019-08-14 20:28 ` bugzilla-daemon
2019-08-14 20:33 ` bugzilla-daemon
2019-08-15 14:38 ` bugzilla-daemon
2019-08-15 16:45 ` bugzilla-daemon
2019-08-15 17:07 ` bugzilla-daemon
2019-08-15 17:11 ` bugzilla-daemon
2019-08-15 17:56 ` bugzilla-daemon
2019-08-15 18:33 ` bugzilla-daemon
2019-08-16 8:22 ` bugzilla-daemon
2019-08-16 14:35 ` bugzilla-daemon
2019-08-16 14:38 ` bugzilla-daemon
2019-08-16 15:20 ` bugzilla-daemon
2019-08-16 18:02 ` bugzilla-daemon
2019-08-16 20:51 ` bugzilla-daemon
2019-08-17 8:09 ` bugzilla-daemon
2019-08-22 13:39 ` bugzilla-daemon
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