This bug was filed from the Socorro interface and is report bp-20c02353-9114-439d-9d8d-a347b2151128. ============================================================= There has long been a low baseline of EXCEPTION_BREAKPOINT crashes in nsDisplayList::HitTest. However, there's clearly a new crash that appeared on Windows, starting in nightly 20151127030231, of EXCEPTION_ACCESS_VIOLATION_READ crashes in nsDisplayList::HitTest. A search for all such crashes on the nightly channel since August is here: https://crash-stats.mozilla.com/signature/?product=Firefox&release_channel=nightly&date=%3E%3D2015-08-01&reason=EXCEPTION_ACCESS_VIOLATION_READ&signature=nsDisplayList%3A%3AHitTest&_columns=date&_columns=product&_columns=version&_columns=build_id&_columns=platform&_columns=reason&_columns=address&page=1#aggregations
The regression range for that nightly relative to the previous one is: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=c321d8403851&tochange=47b49b0d3236
Most likely guess is a regression from bug 1168263, causing a crash in code introduced only a week before in https://hg.mozilla.org/mozilla-central/rev/ac7d0d74ced6 .
This should be fixed by bug 1230075.