Some builds randomly fail with this message:

FATAL: L'exécution de la commande a échoué.
hudson.util.IOException2: Failed to join the process
at hudson.Proc$RemoteProc.join(Proc.java:359)
at hudson.Launcher$ProcStarter.join(Launcher.java:280)
at hudson.tasks.Ant.perform(Ant.java:216)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
at hudson.model.AbstractBuild$AbstractRunner.perform(AbstractBuild.java:624)
at hudson.model.Build$RunnerImpl.build(Build.java:176)
at hudson.model.Build$RunnerImpl.doRun(Build.java:138)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:420)
at hudson.model.Run.run(Run.java:1362)
at hudson.matrix.MatrixRun.run(MatrixRun.java:137)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:145)
Caused by: java.util.concurrent.ExecutionException: hudson.remoting.RequestAbortedException: java.io.IOException: Unexpected termination of the channel
at hudson.remoting.Request$1.get(Request.java:218)
at hudson.remoting.Request$1.get(Request.java:172)
at hudson.remoting.FutureAdapter.get(FutureAdapter.java:55)
at hudson.Proc$RemoteProc.join(Proc.java:351)
... 11 more
Caused by: hudson.remoting.RequestAbortedException: java.io.IOException: Unexpected termination of the channel
at hudson.remoting.Request.abort(Request.java:257)
at hudson.remoting.Channel.terminate(Channel.java:680)
at hudson.remoting.Channel$ReaderThread.run(Channel.java:971)
Caused by: java.io.IOException: Unexpected termination of the channel
at hudson.remoting.Channel$ReaderThread.run(Channel.java:953)
Caused by: java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2553)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1296)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at hudson.remoting.Channel$ReaderThread.run(Channel.java:947)

Here is the slave log:

Slave successfully connected and online
ERROR: Connection terminated
java.io.IOException: Unexpected termination of the channel
at hudson.remoting.Channel$ReaderThread.run(Channel.java:953)
Caused by: java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2553)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1296)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at hudson.remoting.Channel$ReaderThread.run(Channel.java:947)
ERROR: [02/25/11 09:59:47] [SSH] Error deleting file.
java.io.IOException: Sorry, this connection is closed.
at com.trilead.ssh2.transport.TransportManager.sendMessage(TransportManager.java:637)
at com.trilead.ssh2.channel.ChannelManager.openSessionChannel(ChannelManager.java:582)
at com.trilead.ssh2.Session.<init>(Session.java:40)
at com.trilead.ssh2.Connection.openSession(Connection.java:1047)
at com.trilead.ssh2.Connection.exec(Connection.java:1434)
at hudson.plugins.sshslaves.SSHLauncher.afterDisconnect(SSHLauncher.java:597)
at hudson.slaves.SlaveComputer$2.onClosed(SlaveComputer.java:320)
at hudson.remoting.Channel.terminate(Channel.java:695)
at hudson.remoting.Channel$ReaderThread.run(Channel.java:971)
Caused by: java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:168)
at com.trilead.ssh2.crypto.cipher.CipherInputStream.fill_buffer(CipherInputStream.java:41)
at com.trilead.ssh2.crypto.cipher.CipherInputStream.internal_read(CipherInputStream.java:52)
at com.trilead.ssh2.crypto.cipher.CipherInputStream.getBlock(CipherInputStream.java:79)
at com.trilead.ssh2.crypto.cipher.CipherInputStream.read(CipherInputStream.java:108)
at com.trilead.ssh2.transport.TransportConnection.receiveMessage(TransportConnection.java:232)
at com.trilead.ssh2.transport.TransportManager.receiveLoop(TransportManager.java:672)
at com.trilead.ssh2.transport.TransportManager$1.run(TransportManager.java:470)
at java.lang.Thread.run(Thread.java:662)
[02/25/11 09:59:47] [SSH] Connection closed.
ERROR: [02/25/11 09:59:47] lagent esclave a été terminé
java.io.IOException: Unexpected termination of the channel
at hudson.remoting.Channel$ReaderThread.run(Channel.java:953)
Caused by: java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2553)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1296)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at hudson.remoting.Channel$ReaderThread.run(Channel.java:947)
FATAL: channel is already closed
hudson.remoting.ChannelClosedException: channel is already closed
at hudson.remoting.Channel.send(Channel.java:466)
at hudson.remoting.Request.call(Request.java:105)
at hudson.remoting.Channel.call(Channel.java:629)
at hudson.Launcher$RemoteLauncher.kill(Launcher.java:744)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:443)
at hudson.model.Run.run(Run.java:1362)
at hudson.matrix.MatrixRun.run(MatrixRun.java:137)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:145)
Caused by: java.io.IOException: Unexpected termination of the channel
at hudson.remoting.Channel$ReaderThread.run(Channel.java:953)
Caused by: java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2553)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1296)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at hudson.remoting.Channel$ReaderThread.run(Channel.java:947)