Re: Gigantic memory leak in linux-2.6.[789]!

["Kristian Sørensen" <ipqw@users.sourceforge.net>]

Richard B. Johnson wrote:
> On Fri, 22 Oct 2004, Kasper Sandberg wrote:
> 
>> On Fri, 2004-10-22 at 16:13 +0200, Kristian Sørensen wrote:
>>
>>> Hi all!
>>>
>>> After some more testing after the previous post of the OOPS in
>>> generic_delete_inode, we have now found a gigantic memory leak in 
>>> Linux 2.6.
>>> [789]. The scenario is the same:
>>>
>>> File system: EXT3
>>> Unpack and delete linux-2.6.8.1.tar.bz2 with this Bash while loop:
>>>
>>> let "i = 0"
>>> while [ "$i" -lt 10 ]; do
>>>    tar jxf linux-2.6.8.1.tar.bz2;
>>>    rm -fr linux-2.6.8.1;
>>>    let "i = i + 1"
>>> done
>>>
>>> When the loop has completed, the system use 124 MB memory more _each_ 
>>> time....
>>> so it is pretty easy to make a denial-of-service attack :-(
> 
> 
> 
> Do something like this with your favorite kernel version.....
> 
> while true ; do tar -xzf linux-2.6.9.tar.gz ; rm -rf linux-2.6.9 ; 
> vmstat ; done
> 
> You can watch this for as long as you want. If there is no other
> activity, the values reported by vmstat remain, on the average, stable.
> If you throw in a `sync` command, the values rapidly converge to
> little memory usage as the disk-data gets flused to disk.
The problem is, that the free memory reported by vmstat is decresing by 
124mb for each 10-iterations....

The allocated memory does not get freed even if the system has been left 
alone for three hours!


Cheers, Kristian.

-- 
Kristian Sørensen
- The Umbrella Project
   http://umbrella.sourceforge.net

E-mail: ipqw@users.sf.net, Phone: +45 29723816