1353959 - Need a test webextension to crash the extension process

Status: RESOLVED FIXED

(WebExtensions :: General, defect, P1)

Description

[krupa raj [:krupa--use this to needinfo]]

Is it possible to build a webextension that would allow to trigger a crash in the extension process to test how well Firefox recovers for out of process?

Comment 1

[Kris Maglione [:kmag]]

No, it's not possible. We could do it with an unsigned add-on on non-release builds, but I can answer the question for you now: We don't currently make any attempt to recover from an extension process crash, so filing a bug for that would probably be the place to start.

Comment 2

[Kris Maglione [:kmag]]

This should be doable with a simple browser console code snippet.

Comment 3

[Kris Maglione [:kmag]]

Running this in the browser console should do:

Cu.import("resource://gre/modules/Extension.jsm").GlobalManager.extensionMap.values().next().value.parentMessageManager.loadProcessScript("data:,Components.utils.import('resource://gre/modules/ctypes.jsm'); ctypes.cast(ctypes.uintptr_t(1), ctypes.int.ptr).contents", false);

Comment 4

[Kris Maglione [:kmag]]

I've been told this would be more impressive without any semicolons, so:

Cu.import("resource://gre/modules/Extension.jsm").GlobalManager.extensionMap.values().next().value.parentMessageManager.loadProcessScript("data:,Components.utils.import('resource://gre/modules/ctypes.jsm').ctypes.cast(ctypes.uintptr_t(1), ctypes.int.ptr).contents", false);

Comment 5

[CosminB]

Attachment: Crash2.gif

Using the snippet from comment 4 will cause Firefox to crash, do you have any opinion about this Kris? 

Here is the crash report: https://crash-stats.mozilla.com/report/index/ded6c3d8-ebc8-4b2a-9e9c-cdc260170427

Verified on Firefox 55.0a1 (2017-04-27) under Wind 7 -64 bit.

Please see the attached file.

Comment 6

[Kris Maglione [:kmag]]

Currently, WebExtensions normally run in the main browser process, so that's what this snippet will crash. If you set "extensions.webextensions.remote" to true, it will crash the separate extensions process.

Comment 7

[CosminB]

Attachment: CrashExtensionsProcess.gif

I can confirm that using the snippet from comment 4 after "extensions.webextensions.remote" was set to true will crash the extensions process.

As you can see in the attached video,the WebExtensions will not work after the crash of the extensions process.

This issue is verified as fixed on Firefox 55.0a1 (2017-04-28) under Wind 7 64-bit and Ubuntu 16.04 32-bit.