I don't think that this is meant to impact add-on code at all, unless it is calling browser code and making it do something unsafe, in which case it would be up to the add-on developer to fix that. It's probably worth filing a bug to track what is going on there though.
On Thu, Jan 28, 2016 at 6:36 AM, Honza Bambas <hbam...@mozilla.com> wrote: > Do we have any agenda for extensions? I'm using FireGestures and it's broken > since this has landed, just shouting out a lot of "unsafe CPOW usage" > (missing the "forbidden" tho). > > Is the action here limited to just file a bug on the add-on side to fix this > or can we do anything on our side? (I presume and also support that add-ons > should be fixed here.) > > Thanks. > > -hb- > > > On 1/27/2016 17:42, Mike Conley wrote: >> >> The spaghetti was put in the machine last night - this work has now >> landed on mozilla-central. >> >> If you start seeing "unsafe CPOW usage forbidden" in the Browser Console >> for various things, please mark them blocking bug 1233497. >> >> Thanks all, >> >> -Mike >> >> On 20/01/2016 3:54 PM, Mike Conley wrote: >>> >>> (cross-posted to both dev-platform and firefox-dev) >>> * >>> * >>> TL;DR: Shortly, I’ll be flipping a pref to outlaw unsafe CPOWs in almost >>> all browser code. Unsafe CPOWs inside add-on scopes should continue to >>> work properly. If you start seeing "unsafe CPOW usage forbidden” errors >>> being throw for a feature you’re working on in the Browser Console, it’s >>> because unsafe CPOWs have been outlawed and you should stop using them. >>> Talk to me if you run into problems. >>> >>> Details: >>> >>> “unsafe” CPOWs[1][2] are CPOWs that are accessed when the other process >>> is not currently blocked waiting for information from you. For example, >>> if you access gBrowser.selectedBrowser.contentDocumentAsCPOW.body when >>> the content process is garbage collecting, the parent will be blocked >>> until the child decides that it has a moment to service the synchronous >>> message and return the information that the parent needs. Unsafe CPOWS >>> are generally pretty horrible for performance, especially because we >>> cannot know what state the other process is in. >>> >>> “safe” CPOWs are when the other process is in a known blocked state - >>> for example, the content process sends a synchronous message to the >>> parent asking for some information, and is blocked waiting for a >>> response. The parent then accesses CPOWs in the content process safely, >>> because the content process is in a known state. The only overhead here >>> is the IPC traffic. >>> >>> “unsafe” CPOWs are often used by add-ons to synchronously manipulate >>> content. A year or so back, a bunch of browser code also used unsafe >>> CPOWs in this way, but we’ve been slowly but surely weeding them out. >>> We’re at the state now where we believe we’ve eliminated most of the >>> in-browser unsafe CPOW uses[3]. >>> >>> Within the next day or so, I’m going to be landing bug 1233497[4] which >>> will cause unsafe CPOW usage in non-addon browser code to throw. In the >>> event that this breaks things horribly, there is a pref[5] that we can >>> flip to turn unsafe CPOWs back on while we fix things. >>> >>> Again, this work is occurring in bug 1233497[4]. If there are any major >>> concerns, please bring them up here before I throw the spaghetti into >>> the machine. >>> >>> For more details on unsafe CPOWs, please read [1] and/or [2]. >>> >>> [1]: >>> https://mikeconley.ca/blog/2015/02/17/on-unsafe-cpow-usage-in-firefox-desktop-and-why-is-my-nightly-so-sluggish-with-e10s-enabled/ >>> >>> [2]: http://blog.lassey.us/2015/01/10/unsafe-cpow-usage/ >>> [3]: Outside of tests, and a few other little things that there are >>> follow-ups for. >>> [4]: https://bugzilla.mozilla.org/show_bug.cgi?id=1233497 >>> [5]: dom.ipc.cpows.forbid-unsafe-from-browser >>> >> _______________________________________________ >> dev-platform mailing list >> dev-platform@lists.mozilla.org >> https://lists.mozilla.org/listinfo/dev-platform > > > > _______________________________________________ > dev-platform mailing list > dev-platform@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-platform _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
