* Re: Recent mm changes leading to filesystem corruption?
[not found] <20061216155044.GA14681@deprecation.cyrius.com>
@ 2006-12-16 18:20 ` Hugh Dickins
2006-12-16 18:44 ` Martin Michlmayr
2006-12-16 20:55 ` Peter Zijlstra
1 sibling, 1 reply; 5+ messages in thread
From: Hugh Dickins @ 2006-12-16 18:20 UTC (permalink / raw)
To: Martin Michlmayr; +Cc: Peter Zijlstra, linux-mm, linux-kernel, debian-kernel
On Sat, 16 Dec 2006, Martin Michlmayr wrote:
> Debian recently applied a number of mm changes that went into 2.6.19
> to their 2.6.18 kernel for LSB 3.1 compliance (msync() had problems
> before). Since then, some filesystem corruption has been observed
> which can be traced back to these mm changes. Is anyone aware of
> problems with these patches?
Very disturbing. I'm not aware of any problem with them, and we
surely wouldn't have released 2.6.19 with any known-corrupting patches
in. There's some doubts about 2.6.19 itself in the links below: were
it not for those, I'd suspect a mismerge of the pieces into 2.6.18,
perhaps a hidden dependency on something else. I'll ponder a little,
but let's CC linux-mm in case someone there has an idea.
Hugh
>
> The patches that were applied are:
>
> - mm: tracking shared dirty pages
> - mm: balance dirty pages
> - mm: optimize the new mprotect() code a bit
> - mm: small cleanup of install_page()
> - mm: fixup do_wp_page()
> - mm: msync() cleanup
>
> With these applied to 2.6.18, the Debian installer on a slow ARM
> system fails because a program segfaults due to filesystem corruption:
> http://bugs.debian.org/401980 This problem also occurs if you only
> apply the "mm: tracking shared dirty pages" patch to 2.6.18 from the
> series of 5 patches listed above.
>
> Another problem has been reported related to libtorrent: according to
> http://bugs.debian.org/402707 someone also saw this with non-Debian
> 2.6.19 but obviously it's hard to say whether the bugs are really
> related.
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=394392;msg=24 shows
> some dmesg messages but again it's not 100% clear it's the same bug.
>
> Has anyone else seen problems or is aware of a fix to the patches
> listed above that I'm unaware of? It's possible the problem only
> shows up on slow systems. (The corruption is reproducible on a slow
> NSLU2 ARM system with 32 MB ram, but it doesn't happen on a faster ARM
> box with more RAM.)
> --
> Martin Michlmayr
> http://www.cyrius.com/
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: Recent mm changes leading to filesystem corruption?
[not found] <20061216155044.GA14681@deprecation.cyrius.com>
2006-12-16 18:20 ` Recent mm changes leading to filesystem corruption? Hugh Dickins
@ 2006-12-16 20:55 ` Peter Zijlstra
2006-12-16 21:23 ` Martin Michlmayr
1 sibling, 1 reply; 5+ messages in thread
From: Peter Zijlstra @ 2006-12-16 20:55 UTC (permalink / raw)
To: Martin Michlmayr
Cc: Hugh Dickins, linux-kernel, debian-kernel, linux-mm, David Miller
On Sat, 2006-12-16 at 16:50 +0100, Martin Michlmayr wrote:
> Debian recently applied a number of mm changes that went into 2.6.19
> to their 2.6.18 kernel for LSB 3.1 compliance (msync() had problems
> before). Since then, some filesystem corruption has been observed
> which can be traced back to these mm changes. Is anyone aware of
> problems with these patches?
As said by Hugh, no we were not.
> The patches that were applied are:
>
> - mm: tracking shared dirty pages
> - mm: balance dirty pages
> - mm: optimize the new mprotect() code a bit
> - mm: small cleanup of install_page()
> - mm: fixup do_wp_page()
> - mm: msync() cleanup
>
> With these applied to 2.6.18, the Debian installer on a slow ARM
> system fails because a program segfaults due to filesystem corruption:
> http://bugs.debian.org/401980 This problem also occurs if you only
> apply the "mm: tracking shared dirty pages" patch to 2.6.18 from the
> series of 5 patches listed above.
This made me think of a blog entry by DaveM from some time ago:
http://vger.kernel.org/~davem/cgi-bin/blog.cgi/2006/06/09
> Another problem has been reported related to libtorrent: according to
> http://bugs.debian.org/402707 someone also saw this with non-Debian
> 2.6.19 but obviously it's hard to say whether the bugs are really
> related.
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=394392;msg=24 shows
> some dmesg messages but again it's not 100% clear it's the same bug.
>
> Has anyone else seen problems or is aware of a fix to the patches
> listed above that I'm unaware of? It's possible the problem only
> shows up on slow systems. (The corruption is reproducible on a slow
> NSLU2 ARM system with 32 MB ram, but it doesn't happen on a faster ARM
> box with more RAM.)
What is not clear from all these reports is what architectures this is
seen on. I suspect some of them are i686, which together with the
explicit mention of ARM make it a cross platform issue.
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^ permalink raw reply [flat|nested] 5+ messages in thread