1863615 - Performing a clean shutdown of a utility process does not send profiler data to the parent

Status: NEW

(Core :: IPC, task)

Description

[Ray Kraesig [:rkraesig]]

When a utility process is shut down, it's ultimately killed rather than actually shutting down cleanly.

A consequence of this is that, if the Firefox profiler is running, the utility process' profiler data is lost; it never gets a chance to send its profiler data back to the parent.

Comment 1

[:gerard-majax]

Can you elaborate what is lost? There is test, so we definitively verify there is data sent.

Comment 2

[:gerard-majax]

https://searchfox.org/mozilla-central/source/ipc/glue/test/browser/browser_utility_profiler.js

Comment 3

[:gerard-majax]

Are we missing something like https://searchfox.org/mozilla-central/source/dom/ipc/ContentChild.cpp#3050-3051 ?

Comment 4

[:gerard-majax]

(going to sleep so just brain dump) what if we add mProfilerController->GrabShutdownProfileAndShutdown(); to https://searchfox.org/mozilla-central/source/ipc/glue/UtilityProcessChild.cpp#143-151 ?

Comment 5

[:gerard-majax]

Attachment: WIP: Bug 1863615 - Update test to reproduce lack of profile when Utility shuts down before profiler

Comment 6

[:gerard-majax]

So bug 1529131 already has the solution, it never landed, and attached is a patch that adds testing

Comment 7

[Ray Kraesig [:rkraesig]]

(In reply to :gerard-majax from comment #4)

(going to sleep so just brain dump) what if we add mProfilerController->GrabShutdownProfileAndShutdown(); to https://searchfox.org/mozilla-central/source/ipc/glue/UtilityProcessChild.cpp#143-151 ?

Since the needinfo is still up: I'm not sure that would work — I don't think the utility process ever actually goes through its shutdown sequence. Or at least I don't think anything blocks on it doing so, so it could get Terminate()d halfway through.

Bug 1529131 does look like what's needed, at a cursory glance.