On Thu, Jan 28, 2016 at 10:16 AM, Mike Conley <mcon...@mozilla.com> wrote:
> Add-ons that are not yet marked multi-process compatible will use our > shimming layer, which allows usage of unsafe CPOWs within add-on code / > compartments. > > At least part of the problem here appears to be that FireGestures has > "multiprocessCompatible" set to true in its install.rdf: > > > https://github.com/gomita/firegestures/blob/7bd7db329c985dece9717105b07ede6303827a3d/install.rdf#L317 > > This will cause it to bypass our shim layer, which means it doesn't get a > free pass on using CPOWs anymore. > I'm not sure this is the problem. The patch in bug 1233497 just looks at whether an add-on is making the CPOW request. It doesn't know anything about shims or multiprocessCompatible. > > I'll see if I can make some recommendations to that add-on author in the > associated GitHub issue: https://github.com/gomita/firegestures/issues/116 > > On 28 January 2016 at 11:57, Dave Townsend <dtowns...@mozilla.com> wrote: > > > 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 > > > _______________________________________________ > 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
