[paramiko] paramiko stops responding after huge data is transferred !

[Dwayne Litzenberger]

I saw this behaviour too, recently.  I was going to see if I could reproduce 
it, but apparently you've done that for me.

On March 15, 2008 07:26:26 am Deepak Rokade wrote:
> Hi All,
> I am using paramiko 1.5.3 in my python application.
> I found that when large data is fetched using paramiko with prefetch,
> deadlock condition occurs.
> I found through paramiko debug level logs, that deadlock occurs when
> paramiko goes for rekeying.
> Below is the paramiko log.
>
> DEB [20080315-18:27:58.843] thr=1   paramiko.transport: Rekeying (hit 91
> packets, 1051212 bytes received)
>
> Above is the last log I saw after which my application stopped responding.
>
> For reproducing deadlock quickly, I had set the low limit for
> REKEY_PACKETS. I set the limit as
>     REKEY_PACKETS = pow(2, 20)
>     REKEY_BYTES = pow(2, 20)
> (In file paramiko/packet.py , class Packetizer)
>
>
> For tackling this problem I close connections periodically.
> Has this problem been solved in later verion of paramiko ?.
>
> I tried paramiko 1.7.1 for short test in which I did not observe deadlock
> condition even after setting REKEY_PACKETS limit.
> Below are the debug logs.
>
> DEB [20080315-18:23:00.193] thr=6   paramiko.transport: Switch to new keys
> ...
> DEB [20080315-18:23:00.467] thr=6   paramiko.transport: Rekeying (hit 91
> packets, 1049340 bytes received)
> DEB [20080315-18:23:00.571] thr=6   paramiko.transport: kex
> algos:['diffie-hellman-group-exchange-sha1', 'diffie-hellman-group1-sha1']
> server
>  key:['ssh-rsa', 'ssh-dss'] client encrypt:['aes128-cbc', '3des-cbc',
> 'blowfish-cbc', 'cast128-cbc', 'arcfour', 'aes192-cbc', 'aes256-cbc', '
> rijndael-cbc at lysator.liu.se', 'aes128-ctr', 'aes192-ctr', 'aes256-ctr']
> server encrypt:['aes128-cbc', '3des-cbc', 'blowfish-cbc', 'cast128-cb
> c', 'arcfour', 'aes192-cbc', 'aes256-cbc', 'rijndael-cbc at lysator.liu.se',
> 'aes128-ctr', 'aes192-ctr', 'aes256-ctr'] client mac:['hmac-md5', '
> hmac-sha1', 'hmac-ripemd160', 'hmac-ripemd160 at openssh.com', 'hmac-sha1-96',
> 'hmac-md5-96'] server mac:['hmac-md5', 'hmac-sha1', 'hmac-ripemd1
> 60', 'hmac-ripemd160 at openssh.com', 'hmac-sha1-96', 'hmac-md5-96'] client
> compress:['none', 'zlib'] server compress:['none', 'zlib'] client la
>
>
> However I am not sure if this problem is actually solved in version 1.7.1
> Please guide.



-- 
Dwayne Litzenberger, B.A.Sc.
Information Technology Analyst

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