Sometimes I see this error:

[10/09/15 14:38:27] [SSH] Opening SSH connection to 10.6.5.9:22.
[10/09/15 14:38:28] [SSH] Authentication successful.
[10/09/15 14:38:28] [SSH] The remote users environment is:
HOME='/home/myaccount'
IFS='
'
LOGNAME='myaccount'
OPTIND='1'
PATH='/usr/bin:/bin'
PPID='9230'
PS1='\w \$ '
PS2='> '
PS4='+ '
PWD='/home/myaccount'
SHELL='/bin/sh'
USER='myaccount'
[10/09/15 14:38:28] [SSH] Starting sftp client.
[10/09/15 14:38:28] [SSH] SFTP failed. Copying via SCP.
[10/09/15 14:38:28] [SSH] Copying latest slave.jar...
Expanded the channel window size to 4MB
[10/09/15 14:38:28] [SSH] Starting slave process: cd "/home/myaccount" && /opt/jre/bin/java -jar slave.jar
<===[JENKINS REMOTING CAPACITY]===>channel started
Slave.jar version: 2.52
This is a Unix slave
Segmentation fault
ERROR: Connection terminated
java.io.IOException: Unexpected EOF
at hudson.remoting.ChunkedInputStream.readUntilBreak(ChunkedInputStream.java:99)
at hudson.remoting.ChunkedCommandTransport.readBlock(ChunkedCommandTransport.java:39)
at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)
ERROR: Failed to install restarter
hudson.remoting.ChannelClosedException: channel is already closed
at hudson.remoting.Channel.send(Channel.java:575)
at hudson.remoting.Request.call(Request.java:130)
at hudson.remoting.Channel.call(Channel.java:777)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller.install(JnlpSlaveRestarterInstaller.java:52)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller.access$000(JnlpSlaveRestarterInstaller.java:33)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller$1.call(JnlpSlaveRestarterInstaller.java:39)
at jenkins.slaves.restarter.JnlpSlaveRestarterInstaller$1.call(JnlpSlaveRestarterInstaller.java:36)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.io.IOException: Unexpected EOF
at hudson.remoting.ChunkedInputStream.readUntilBreak(ChunkedInputStream.java:99)
at hudson.remoting.ChunkedCommandTransport.readBlock(ChunkedCommandTransport.java:39)
at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)
Slave successfully connected and online
ERROR: Failed to update jenkins-slave.exe
Slave JVM has terminated. Exit code=139
java.io.IOException: remote file operation failed: /home/myaccount/jenkins-slave.exe at hudson.remoting.Channel@3902ea91:Freescale-5.9: hudson.remoting.ChannelClosedException: channel is already closed
at hudson.FilePath.act(FilePath.java:985)
at hudson.FilePath.act(FilePath.java:967)
at hudson.FilePath.exists(FilePath.java:1435)
at org.jenkinsci.modules.windows_slave_installer.SlaveExeUpdater$1.call(SlaveExeUpdater.java:46)
at org.jenkinsci.modules.windows_slave_installer.SlaveExeUpdater$1.call(SlaveExeUpdater.java:37)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
Caused by: hudson.remoting.ChannelClosedException: channel is already closed
at hudson.remoting.Channel.send(Channel.java:575)
at hudson.remoting.Request.call(Request.java:130)
at hudson.remoting.Channel.call(Channel.java:777)
at hudson.FilePath.act(FilePath.java:978)
... 9 more
Caused by: java.io.IOException: Unexpected EOF
at hudson.remoting.ChunkedInputStream.readUntilBreak(ChunkedInputStream.java:99)
at hudson.remoting.ChunkedCommandTransport.readBlock(ChunkedCommandTransport.java:39)
at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)
[10/09/15 14:39:03] [SSH] Connection closed.

Sometimes I see this, though:

[10/09/15 14:45:28] [SSH] Starting sftp client.
[10/09/15 14:45:28] [SSH] SFTP failed. Copying via SCP.
[10/09/15 14:45:28] [SSH] Copying latest slave.jar...
Expanded the channel window size to 4MB
[10/09/15 14:45:28] [SSH] Starting slave process: cd "/home/myaccount" && /opt/jre/bin/java -jar slave.jar
<===[JENKINS REMOTING CAPACITY]===>channel started
Slave.jar version: 2.52
This is a Unix slave
Segmentation fault
ERROR: Connection terminated
java.io.IOException: Unexpected EOF
at hudson.remoting.ChunkedInputStream.readUntilBreak(ChunkedInputStream.java:99)
at hudson.remoting.ChunkedCommandTransport.readBlock(ChunkedCommandTransport.java:39)
at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:48)
ERROR: Unexpected error in launching a slave. This is probably a bug in Jenkins.
java.lang.NullPointerException
at org.jenkinsci.modules.systemd_slave_installer.SlaveInstallerFactoryImpl.createIfApplicable(SlaveInstallerFactoryImpl.java:33)
at org.jenkinsci.modules.slave_installer.SlaveInstallerFactory.createIfApplicable(SlaveInstallerFactory.java:29)
at org.jenkinsci.modules.slave_installer.SlaveInstallerFactory.createFor(SlaveInstallerFactory.java:46)
at org.jenkinsci.modules.slave_installer.impl.ComputerListenerImpl.onOnline(ComputerListenerImpl.java:30)
at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:563)
at hudson.slaves.SlaveComputer.setChannel(SlaveComputer.java:371)
at hudson.plugins.sshslaves.SSHLauncher.startSlave(SSHLauncher.java:945)
at hudson.plugins.sshslaves.SSHLauncher.access$400(SSHLauncher.java:133)
at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:711)
at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:696)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
[10/09/15 14:46:04] Launch failed - cleaning up connection
[10/09/15 14:46:04] [SSH] Connection closed.

Before I updated to 1.609.3, it worked without issue.

Java is: java version 1.7.0_60
Java SE Embedded Runtime Environment (build 1.7.0_60-b19, headless)