Loops at 100% CPU after SFTP upload

[kxroberto]

WinXP Home; latest version 2.2.18 (also with 2.2.16):

after I upload a file FileZilla always/reproducibly
loops and comsumes 100%-x CPU . until exit.

( In 2.2.16 I also remember: Looping Filezilla process
didn't stop even if I exited Filezilla GUI; but not
100% sure. )

Robert

[seelie]

Robert: Maybe you are experiencing this?

[ 1338012 ] Filezilla Hangs in SFTP+ClientAliveInterval
​http://sourceforge.net/tracker/index.php?func=detail&aid=1338012&group_id=21558&atid=372241

Yup, it was really annoying, and a workaround is,
comment out or ( set 0 )"ClientAliveInterval" in
/etc/ssh/sshd_config

#ClientAliveInterval 60
#ClientAliveCountMax 3

However, using ClientAliveInterval would be much preferable
for 2 reasons, so this bug should be fixed.

(1) The client alive messages are sent through the encrypted
channel and so not spoofable. But because of this bug of
Filezilla, SFTP users can not use this feature,
and have to use old KeepAlive, which is spoofable and less
secure.

(2) By setting ClientAliveInterval and ClientAliveCountMax
properly, connections won't die easily even if the route is
not very stable and is down temporarily. Better than using
KeepAlive for this reason too.

[gbruno]

This also happens in the latest current release (2.26a)
and on Win XP Pro with SP2.

Here are the steps to reproduce it - does not take much
and does not need to have a file transfer in process. I
have seen this happen with all SFTP sites I use, so I
doubt if it is server related.

Just open an sftp connection in FileZilla, and wait 1-2
minutes with no activity. Immediately the CPU utilization
jumps to 100%.

If I turn on trace, I see the following messages
continuously appearing:

...
Trace: SftpControlSocket.cpp(2596): OnReceive(10058)
caller=0x003bcddc
Trace: SftpControlSocket.cpp(2596): OnReceive(10058)
caller=0x003bcddc
Trace: SftpControlSocket.cpp(2596): OnReceive(10058)
caller=0x003bcddc
Trace: SftpControlSocket.cpp(2596): OnReceive(10058)
caller=0x003bcddc
...
continues forever until connection is stopped.

You do not need to kill Filezilla - just stopping the SFTP
connection is good enough - the CPU utilization drops to
normal.

Hope that helps.

Mukesh

[seelie]

@gbruno

I
have seen this happen with all SFTP sites I use, so I
doubt if it is server related.

I'm using Filezilla for SFTP using SSH2 for a long time,
and everything is ok as long as
ClientAliveInterval is set to zero, server-side.

and wait 1-2 minutes with no activity

It seems that the problem will happen when
ClientAliveInterval (def 15) * ClientAliveCountMax (def 3)
seconds elapsed, when ssh clients will be disconnected.

I already reported about "SftpControlSocket.cpp(2596)" too.
​http://sourceforge.net/tracker/index.php?func=detail&aid=1338012&group_id=21558&atid=372241

[Alexander Schuch]

It seems as if this bug and "[ 1338012 ] Filezilla Hangs in SFTP+ClientAliveInterval" are related. Can you please test latest FileZilla 2 and FileZilla 3 beta to see if the bug is still there?

[sf-robot]

This Tracker item was closed automatically by the system. It was
previously set to a Pending status, and the original submitter
did not respond within 14 days (the time period specified by
the administrator of this Tracker).