[JENKINS-38527] Slave#createLauncher relies on autoboxing and can thrown NPE

[timja]

in hudson.model.Slave#createLauncher
hudson.Launcher.RemoteLauncher#RemoteLauncher(TaskListener,VirtualChannel,boolean) is invoked using Computer.isUnix() as argument, which return a Boolean. Autoboxing let us do such thing, but can result in NPE.

---

Originally reported by ndeloof, imported from: Slave#createLauncher relies on autoboxing and can thrown NPE

• assignee: oleg_nenashev
• status: Resolved
• priority: Minor
• resolution: Fixed
• resolved: 2017-06-26T09:03:32+00:00
• imported: 2022/01/10

[timja]

oleg_nenashev:

Not a real defect since IsUnix command does not return null. But it still makes sense to fix that.

public Launcher createLauncher(TaskListener listener) throws IOException, InterruptedException {
if(channel==null)
    return new LocalLauncher(listener);
else
    return new RemoteLauncher(listener,channel,channel.call(new IsUnix()));
    }

    private static final class IsUnix extends MasterToSlaveCallable {
public Boolean call() throws IOException {
    return File.pathSeparatorChar==':';
}
private static final long serialVersionUID = 1L;
    }

[timja]

oleg_nenashev:

We hit it in another logic branch. I will fix it

[timja]

oleg_nenashev:

https://github.com/jenkinsci/jenkins/pull/2923

[timja]

scm_issue_link:

Code changed in jenkins
User: Oleg Nenashev
Path:
core/src/main/java/hudson/model/Slave.java
http://jenkins-ci.org/commit/jenkins/78a42d5a4a5d545324c2d3230de6947e1ec8806e
Log:
JENKINS-38527 - Prevent NullPointerException in Slave#createLauncher() and add cause diagnostics (#2923)

• JENKINS-38527 - Prevent NullPointerException in Slave#createLauncher() and add cause diagnostics

The original issue comes from the isUnix() unboxing, but we can also get into an issue later if we pass a null Channel instance to the logic.
This change adds some diagnostics which discovers potential root causes of such potential NPEs due to the race conditions with Computer reconnection

• JENKINS-38527 - Also handle cases when Channel#isClosingOrClosed() as @stephenc suggested

[timja]

oleg_nenashev:

The pull request has been merged towards 2.68. Marking as LTS candidate

[timja]

scm_issue_link:

Code changed in jenkins
User: Oleg Nenashev
Path:
core/src/main/java/hudson/model/Slave.java
http://jenkins-ci.org/commit/jenkins/c2163c5b3cb4a0c42cdc31cf404a82bcecb05082
Log:
JENKINS-38527 - Prevent NullPointerException in Slave#createLauncher() and add cause diagnostics (#2923)

• JENKINS-38527 - Prevent NullPointerException in Slave#createLauncher() and add cause diagnostics

The original issue comes from the isUnix() unboxing, but we can also get into an issue later if we pass a null Channel instance to the logic.
This change adds some diagnostics which discovers potential root causes of such potential NPEs due to the race conditions with Computer reconnection

• JENKINS-38527 - Also handle cases when Channel#isClosingOrClosed() as @stephenc suggested

(cherry picked from commit 78a42d5a4a5d545324c2d3230de6947e1ec8806e)

[timja]

[Originally duplicated by: JENKINS-23305]