firefox crashes on an M1 macbook

[Jan Stary]

This is current/arm64 on an Apple M1 MacBook Air (dmesg below).
While everything mostly works, Firefox keeps crashing.

Reproducibly, it always crashes on calendar.google.com;
_sometimes_ it crashes when playing a video.
On simple sites, it works withotu problems.

How can I debug this?  Is it related to
the lack of video acceleration on these machines?

        Thanks,

                Jan