I've reproduced the issue by browsing around instantluxe.co.uk on my linux machine and reported https://bugs.chromium.org/p/chromium/issues/detail?id=616190 for the crash with Crash ID ef03aaaa00000000 

Thanks for reproducing.
Can we disable http2 now on the website, so our customers aren't affected by the issue?

Yes, I think you should disable HTTP/2 at this point.  I'll try to investigate based on the crash and net-internals.  Thank you.

Thanks, done.
Please let me know if you need me to re-enable it for further investigation.

I cannot reproduce this crash with neither Debug nor Release locally-built Chrome 53.0.2754.0.

Could you try this on Canary or Dev channel (https://www.chromium.org/getting-involved/dev-channel) to confirm?

Hrm, just reading comment 5 I wonder whether my recent non-reproduction is the result of HTTP/2 being disabled on the site and not of different Chrome version.

I just re-enabled h2 on the server to check Version 53.0.2754.0 canary (64-bit) on a Win10 machine: the crash is still present.
h2 is disabled again on the host.

I'd like to help you diagnose the problem if I can. How can I help?
(I can't see #616190)

g.rossolini@ would it be possible for you to bring up a cnamed host (h2.yourdomain.com) with h2 enabled, so we can diagnose this?

Sure, please use www.instantluxe.cn.

I cannot reproduce the crash when browsing www.instantluxe.cn with Chrome Dev 55.0.2859.0.  I confirm that HTTP/2 is used.  If anybody sees the crash, please post the crash ID from chrome://crashes/.

I just tried again with both 53.0.2785.116 (64-bit) and Version 55.0.2867.0 canary (64-bit).
Canary does not crash any more, while Stable still crashes.
I am guessing something has been done to resolve this?

It is possible that this crash got fixed in the meanwhile.

Note, however, that right now I cannot reproduce the crash with either 55.0.2859.0 or 53.0.2785.116, both 64 bit on Linux, browsing www.instantluxe.cn for five minutes, even though HTTP/2 was negotiated in both cases.

Is it possible to know what Chrome version comes with the fix and whether the fix was accidental?
With macOS, Version 53.0.2785.116 (64-bit) still crashes after a few pageloads on www.instantluxe.cn while Version 55.0.2870.0 canary (64-bit) is stable.

One could bisect to find the change that fixed the crash, and that would tell us what version comes with the fix and whether it was accidental.  However, given that one can browse for many minutes without encountering the crash, this approach would be infeasible.

Marking as fixed as the OP reports that 55.0.2870.0 does not crash.

Comment #2 could reproduce the issue at the time. Would you mind getting in touch with that person to make sure we're not missing anything?
Without bisecting anything, Issue #616190 was reported because of this here, so I guess resolution could be tracked from there?
I can't attach a crash ID when browsing with a guest user, but I am attaching two net-internals reports saved from two user sessions with Version 53.0.2785.116 (64-bit) (on macOS Sierra Version 10.12 (16A323)).

My take on this bug is that at some point, the connection is negotiated as HTTP/1.1 instead of HTTP/2, and that causes the crash.

Deleted: net-internals-log.json 8.9 MB

net-internals-log.json 8.9 MB View Download

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net-internals-log.json 8.4 MB View Download

This is just to let you know we've enabled h2 again for the last week, and everything seems stable. We have no feedback about issues on this, nor have we noticed any ourselves.
(I am using stable v54.0.2840.71 (64-bit) at the moment)
Thanks for the fix!

Re #22:  Thank you for reporting back.  Please file a new bug if you experience any issues.