2043803 - pref_SetPref: Attempt to write pref media.gmp-manager.buildID after XPCOMShutdownThreads started.

Status: RESOLVED FIXED

(Toolkit :: Add-ons Manager, defect)

Description

[Rob Wu [:robwu]]

Past the end of toolkit/mozapps/extensions/test/xpcshell/test_gmpProvider.js, the test crashed. E.g. the following part of a test log from a Windows debug build:

pref_SetPref: Attempt to write pref media.gmp-manager.buildID after XPCOMShutdownThreads started.
0 setString(aKey = ""media.gmp-manager.buildID"", aVal = ""20260529200249"") ["resource://gre/modules/GMPUtils.sys.mjs":256:20]
    this = [object Object]
1 _versionchangeOccurred() ["resource://gre/modules/GMPInstallManager.sys.mjs":553:14]
    this = [object Object]
2 simpleCheckAndInstall() ["resource://gre/modules/GMPInstallManager.sys.mjs":567:14]
    this = [object Object]
3 checkForUpdates/<() ["resource://gre/modules/addons/GMPProvider.sys.mjs":570:27]
4 notify("[xpconnect wrapped nsITimer @ 0x18612d90 (native @ 0x18603f30)]") ["resource://gre/modules/Timer.sys.mjs":66:16]
    this = [object Object]
[15556] Assertion failure: false (Late preference writes should be avoided.), at checkouts\\gecko\\modules\\libpref\\Preferences.cpp:1910

Judging by the stack trace, looks like it is a timer scheduled during a preference change observer for KEY_EME_ENABLED (media.eme.enabled), through a call to this.checkForUpdates(GMP_CHECK_DELAY); at GMPProvider.sys.mjs:544.
The GMP_CHECK_DELAY here is ten whole seconds! The logic was originally introduced in bug 1145694.

The test_globalEmeDisabled test task in test_gmpProvider.js (source) toggles the preference. If the test takes about 10 seconds after that, then it is possible to trigger the assertion.

Comment 1

[Rob Wu [:robwu]]

Attachment: Bug 2043803 - Avoid GMP update check after shutdown

There is a code path that schedules a 10-second timer before the GMP
update check is triggered (for details, see bug 2043803). That can
potentially result in update checks being kicked off past shutdown,
which is undesirable, so skip it if we are past shutdown.

Comment 2

[Intermittent Failures Robot]

1 failures were associated with this bug in the last 7 days.

Repository breakdown:

• try: 1

Table

	no_variant
windows11-x86/debug	1

For more details, see:

https://treeherder.mozilla.org/intermittent-failures/bugdetails?bug=2043803&startday=2026-05-25&endday=2026-05-31&tree=all

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/bed38205c84d
https://hg.mozilla.org/integration/autoland/rev/d75c213a9ed4
Avoid GMP update check after shutdown r=alwu

Comment 4

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/d75c213a9ed4