git svn clone freezes the pc on ext4

git svn clone freezes the pc on ext4

[Jens Kubieziel]

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Hi,

I recently changed my /home-partition to ext4 and wanted to clone a SVN
repository. After calling "git svn clone https://...", git began
fetching old revisions and at every try the complete pc freezes. It
doesn't respond to any keyboard presses nor to SysRq. I tried the same
command on different filesystems (ext3, reiser) and with different git
versions. Only git on ext4 causes this freeze.

The system logs have no uncommon messages. I found only:
EXT4 FS on sda3, internal journal on sda3:8
EXT4-fs: deleayed allocation enabled
EXT4-fs: file extents enabled
EXT4-fs: mballoc enabled
EXT4-fs: mounted filesystem with ordered data mode
Linux version is 2.6.28-15 (default installation from Ubuntu jaunty).

How can I find out more about this freeze? Is maybe something known what
causes this? Thanks for any hints.

-- 
Jens Kubieziel                                   http://www.kubieziel.de

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Re: git svn clone freezes the pc on ext4

[Eric Sandeen]

Jens Kubieziel wrote:
> Hi,
> 
> I recently changed my /home-partition to ext4 and wanted to clone a SVN
> repository. After calling "git svn clone https://...", git began
> fetching old revisions and at every try the complete pc freezes. It
> doesn't respond to any keyboard presses nor to SysRq. I tried the same
> command on different filesystems (ext3, reiser) and with different git
> versions. Only git on ext4 causes this freeze.
> 
> The system logs have no uncommon messages. I found only:
> EXT4 FS on sda3, internal journal on sda3:8
> EXT4-fs: deleayed allocation enabled
> EXT4-fs: file extents enabled
> EXT4-fs: mballoc enabled
> EXT4-fs: mounted filesystem with ordered data mode
> Linux version is 2.6.28-15 (default installation from Ubuntu jaunty).
> 
> How can I find out more about this freeze? Is maybe something known what
> causes this? Thanks for any hints.

I'd try doing the test on the main console (not X), turn dmesg up (dmesg
-n 8) and make sure sysrq is enabled; I'd try sysrq-t or sysrq-w to get
stack traces for processes.  If really and truly none of that works and
you get no messages, that sounds like a tough one to sort out.

.28 is getting a bit old, I'd probably try a newer upstream kernel as well.

-Eric

Re: git svn clone freezes the pc on ext4

[Jens Kubieziel]

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* Eric Sandeen schrieb am 2009-09-17 um 16:27 Uhr:
> Jens Kubieziel wrote:
> > I recently changed my /home-partition to ext4 and wanted to clone a SVN
> > repository. After calling "git svn clone https://...", git began
> > fetching old revisions and at every try the complete pc freezes. It
> 
> .28 is getting a bit old, I'd probably try a newer upstream kernel as well.

I upgraded to .31 from Ubuntu and cannot reproduce the problem.

Regards,

-- 
Jens Kubieziel                                   http://www.kubieziel.de
"Ähnlich scheitert Anne Will mit ihrem letzten Versuch, die Kanzlerin
mal wirklich fest zu nageln."
http://www.zeit.de/online/2009/13/merkel-anne-will (mittlerweile korrigiert)

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Re: git svn clone freezes the pc on ext4

[Theodore Tso]

On Thu, Sep 17, 2009 at 03:13:56PM +0200, Jens Kubieziel wrote:
> 
> I recently changed my /home-partition to ext4 and wanted to clone a SVN
> repository. After calling "git svn clone https://...", git began
> fetching old revisions and at every try the complete pc freezes. It
> doesn't respond to any keyboard presses nor to SysRq. I tried the same
> command on different filesystems (ext3, reiser) and with different git
> versions. Only git on ext4 causes this freeze.
> 
> The system logs have no uncommon messages. I found only:
> EXT4 FS on sda3, internal journal on sda3:8
> EXT4-fs: deleayed allocation enabled
> EXT4-fs: file extents enabled
> EXT4-fs: mballoc enabled
> EXT4-fs: mounted filesystem with ordered data mode
> Linux version is 2.6.28-15 (default installation from Ubuntu jaunty).

This sounds like the classic Ubuntu Jaunty's default kernel freezes
when deleting large numbers of files.  It didn't occur with stock
mainline 2.6.28, nor with stock mainline 2.6.29, and it bisected to
one of Ubuntu's ext4 patch backports.  No one was able to debug it
further, and I was never able to replicate it on my test systems, so
we ultimately just told people to use a mainstream kernel or a Karmic
beta kernel for people who wanted to use ext4 with Ubuntu Jaunty.

     	    	       	   	     	 - Ted