1509032 - The pingsender leaves behind zombie processes on Linux

Status: RESOLVED WONTFIX

(Toolkit :: Telemetry, enhancement, P2)

Description

[Gabriele Svelto [:gsvelto]]

While using nightly with telemetry enabled I noticed that multiple pingsender  instances had zombie processes left behind. This is peculiar because it points to a flaw in the nsIProcess implementation on Linux. When launching pingsender we use nsIProcess.run() in non-blocking mode which spanws a thread to wait for the generated process:

https://searchfox.org/mozilla-central/rev/55895c49f55073d82d977cb74ec1d3a71ae4b25f/xpcom/threads/nsProcessCommon.cpp#576

This will eventually invoke nsProcess::Monitor() which in turn waitpid()s for the process:

https://searchfox.org/mozilla-central/rev/55895c49f55073d82d977cb74ec1d3a71ae4b25f/xpcom/threads/nsProcessCommon.cpp#272

But apparently something goes amiss. For now I'm filing this in telemetry but I'll move it in XPCOM if it's really a defect in nsIProcess instead of on how we launch pingsender.

Comment 1

[Jan-Erik Rediger [:janerik]]

Those links seem to be cut off.

Comment 2

[Gabriele Svelto [:gsvelto]]

It's a BMO issue apparently (saw people talk about it on #developers). The first link is to xpcom/threads/nsProcessCommon.cpp:576 and the second to xpcom/threads/nsProcessCommon.cpp:272

Comment 3

[Georg Fritzsche [:gfritzsche]]

Are you looking into this issue currently Gabriele?
Or is this filed for future investigation?

Comment 4

[Gabriele Svelto [:gsvelto]]

I will be looking into this ASAP.

Comment 5

[Georg Fritzsche [:gfritzsche]]

Ok, let us know if you need anything from us.

Comment 6

[Alessio Placitelli [:Dexter]]

Hey Gabriele :) Is this still a problem? Can it be closed?

Comment 7

[Gabriele Svelto [:gsvelto]]

I haven't checked if it's still a problem but, if it still is, it will definitely go away with bug 1901326.

Comment 8

[Alessio Placitelli [:Dexter]]

(In reply to Gabriele Svelto [:gsvelto] from comment #7)

I haven't checked if it's still a problem but, if it still is, it will definitely go away with bug 1901326.

Great, let me close this as WONTFIX, we can still reopen it if needed.