openssh unix dev - Nov 2006 - memory leak problem using openssh 3.4p1-263 ons Suse (SLES 8)

Hello,

 

Whenever copying files using ssh (scp) from SLES 8 (openssh 3.4p1-263) to
another box (e.g SLES 8, Solaris 8, Windows XP), the memory of the initial SLES
8 box gets depleted. To make sure this is true I use the free command whilst
copying and see that the used memory reaches 90 / 100%. After the copying is
finished this memory is never released. No memory tool can tell me what happened
to it? Does anyone have an idea?

 

Kind regards, / Met vriendelijke groet,

 

????????????????????????????????

J?r?me Michot

JRC - European Commission

P.O. Box 2

1755 ZG Petten, The Netherlands

E-Mail: jerome.michot at jrc.nl

Tel: +31 224 565471

Fax: +31 224 565632

WWW: http://www.jrc.cec.eu.int <http://www.jrc.cec.eu.int/> 

????????????????????????????????

jerome michot wrote:
> Whenever copying files using ssh (scp) from SLES 8 (openssh
> 3.4p1-263) to another box (e.g SLES 8, Solaris 8, Windows XP), the
> memory of the initial SLES 8 box gets depleted. To make sure this is
> true I use the free command whilst copying and see that the used
> memory reaches 90 / 100%. After the copying is finished this memory
> is never released. No memory tool can tell me what happened to it?
> Does anyone have an idea?
Sounds like the memory just ends up in the buffer cache.  Does your free 
command have "buffers" and "cached" columns?  If so, what do
they show
before and afterward?

If the scp and ssh processes are gone (and it sound like they are) then 
there's nothing ssh or scp can do to leak memory (short of operating 
system bugs, but we can't help you with those).

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
     Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.

Hi Jerome,

On Tue, Nov 28, 2006 at 03:19:06PM +0100, jerome michot
wrote:
> Whenever copying files using ssh (scp) from SLES 8 (openssh
> 3.4p1-263) to another box (e.g SLES 8, Solaris 8, Windows XP), the
> memory of the initial SLES 8 box gets depleted. To make sure this
> is true I use the free command whilst copying and see that the used
> memory reaches 90 / 100%. After the copying is finished this memory
> is never released. No memory tool can tell me what happened to
> it??? Does anyone have an idea?
It is used by Linux for caching pages. Please read
http://sourcefrog.net/weblog/software/linux-kernel/free-mem.html
and possibly also
http://sourcefrog.net/weblog/software/linux-kernel/swap.html

Since the ssh process has exited it can not leak memory. Please do
report any leaks if you find them, however. The characteristics to
look for are that a process uses memory with no relation to the work
being done.

For example; copying a file with scp should not require the entire
file to be buffered, instead chunks of the file are sent after each
other. So if scp uses an amount of memory roughly the size of the
file (test with large files so the overhead is neglectable) right
before it exits, something is wrong.


//Peter