791617 - Race condition at startup prevents remote debugger from starting up on Fennec

Status: RESOLVED WORKSFORME

(DevTools :: Debugger, defect, P2)

Description

[Mike Hommey [:glandium]]

When devtools.debugger.remote-enabled is set to true, sometimes, the remote debug server listens on port 6000 and sometimes not.

From some debugging of the situation, it looks like the socket transport service is not completely initialized at the moment it is called to listen on the port.

Comment 1

[Panos Astithas (he/him) [:past] (please ni?)]

(In reply to Mike Hommey [:glandium] from comment #0)
> When devtools.debugger.remote-enabled is set to true, sometimes, the remote
> debug server listens on port 6000 and sometimes not.
> 
> From some debugging of the situation, it looks like the socket transport
> service is not completely initialized at the moment it is called to listen
> on the port.

I can't reproduce this. Do you have any specific STR? Do you get any errors in the log or the error console? DH_checkInit should throw if the transport is not initialized.

Comment 2

[Mike Hommey [:glandium]]

Unfortunately, as it's a race condition, it happens randomly and at the moment, i can't reproduce, while it happened quite reliably last week.
IIRC, the failure happens on the asyncListen call, with an xpconnect error, and it leads to a "Could not start debugging listener on port 6000" message.

Comment 3

[Panos Astithas (he/him) [:past] (please ni?)]

Hm, I wonder if port 6000 is already taken when that happens. Although from my reading of the code this should happen during the ServerSocket constructor call, but that is also inside the same try/catch.

Comment 4

[Mike Hommey [:glandium]]

IIRC, this is where it was failing:
http://mxr.mozilla.org/mozilla-central/source/netwerk/base/src/nsServerSocket.cpp#32

Comment 5

[Panos Astithas (he/him) [:past] (please ni?)]

I haven't seen this happen lately and I know ochameau fixed some related bugs in that part of the code, so I'm going to close this bug. Feel free to reopen if it ever occurs again.