Since I updated my local build to m-c tip this morning, I've had many instances of pages not loading or loading incompletely. Only a force-refresh has worked. I wasn't experiencing this problem with an m-c tip build from yesterday's round of merges performed by myself. Looking at what has landed on m-c since, bug 1014394 seems the most likely candidate. I'll backout locally to try and confirm.

Hmm.. something our infra would not catch? Weird. Any URLs or just "anything"? Going to try my self. Thanks for the report.

(In reply to Honza Bambas (:mayhemer) from comment #1) > Hmm.. something our infra would not catch? Weird. Any URLs or just > "anything"? Going to try my self. Thanks for the report. bugzilla.mozilla.org bug pages and addons.mozilla.org definitely affected. To reproduce, you'll likely need to use yesterday's nightly to first load those sites. Next, update to today's nightly then revisit those pages. After a forced reload (i.e. ctrl + F5) the specific page seems to no longer exhibits the issue. This is, of course, a problem if you have a lot of affected visited pages.

OK, got it, this is actually regression from bug 995801. Not related to 1014394 at all. Anyway, it just uncovers bug in cache2 code, or actually http channel code that badly handles the missing sec info. Going to provide a patch.

Patrick, please one quick review on this simple and urgent patch. Thanks. The problem was that when we failed to open the cache entry's sec info, not all conditional headers were removed. So, the channel rejected correctly the entry but left the "If-None-Match" request header. It was then getting 304 but provided no content (304 empty body actually), since there were (correctly) no cache entry to read from.

Comment on attachment 8430931 [details] [diff] [review] v1 https://hg.mozilla.org/integration/mozilla-inbound/rev/ea48287c48a7 Thanks, Patrick!

I cherry-picked this to m-c so we could get a nightly respin. https://hg.mozilla.org/mozilla-central/rev/b85b57f05fda

Comment on attachment 8430931 [details] [diff] [review] v1 [Approval Request Comment] Bug caused by (feature/regressing bug #): bug 995801 uncovered it User impact if declined: Needed to uplift the patch in bug 995801 Testing completed (on m-c, etc.): landed last week on m-c Risk to taking this patch (and alternatives if risky): low, as I understand it String or IDL/UUID changes made by this patch: none