User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:38.0) Gecko/20100101 Firefox/38.0 Build ID: 20150125030202 Steps to reproduce: Start Firefox Nightly. Exit, either immediately, or after a few hours of use. Actual results: Firefox closes the window, and then after a bit, I get a crash generated, asking me to submit a crash report, which I do. Expected results: No crash should have been generated.

There are two recorded crashes happening. https://crash-stats.mozilla.com/report/index/9ab0057c-d2fb-43c6-8b3a-041692150125 https://crash-stats.mozilla.com/report/index/15ce787f-b99d-41cc-830d-4e2122150125 This happens in both my 32-bit and 64-bit Nightlies. While I can immediately crash Firefox with my usual profile just by opening and closing it, on a clean profile, opening and closing Firefox immediately does not create a crash. I have to run some websites through it before it does.

(In reply to Bryan Price from comment #1) > on a clean profile, opening and closing Firefox immediately does not > create a crash. I have to run some websites through it before it does. So, you don't have any addons installed in the crashing profile, right ? Also, could you try with e10s OFF ?

The second crash you linked appears to be crashing while starting a new content process, which seems strange. The crash reported therein is one that I would expect to happen consistently every time you interacted with web content.

@pauly: Uh, I forgot about the damn e10s. Maybe that needs to be an indicator on a bug. :/ I have e10s off, always. I have enough trouble when it is on, right now. My normal profile refuses to load even a static HTML page with e10s, evidently due to the extensions I currently have. I'll run an e10s on my clean profile if I think of it. But, I don't tend to run that profile too often unless it's for debugging purposes. @jdm: I've noticed that the these two happen a minute apart from each other. And this is when I'm shutting down or restarting for a new build. Since the clean profile doesn't crash every time, maybe I should go through and see what extension (or combination thereof) gets me crashing 100% of the time. That might point to why the thing is crashing. I'll see if I can't work on that today.

Several new crash bugs have been filed in recent days containing PCompositorParent. Some are listed in https://bugzilla.mozilla.org/buglist.cgi?f1=OP&o3=substring&list_id=11958282&short_desc=CompositorParent&bug_severity=critical&bug_severity=major&bug_severity=normal&f0=OP&v3=crash&o2=anywordssubstr&f4=CP&chfieldto=Now&query_format=advanced&j1=OR&f3=keywords&chfieldfrom=5m&f2=short_desc&short_desc_type=allwordssubstr&f5=CP&v2=crash%20segfault

Bug 1127270 is already filed with the same crash signature.