From:  Nicholas Nethercote <n.nethercote@gmail.com>
Date:  11 Nov 2016 06:39:23 Hong Kong Time
Newsgroup:  news.mozilla.org/mozilla.dev.tech.js-engine.internals
Subject:  

Re: PSA: Crash reports from crashes in SpiderMonkey now have moz crash reasons

NNTP-Posting-Host:  63.245.214.181

[CC'ing the stability list]

Oh, nice! I hadn't even realized that this problem existed. 'moz crash
reason' is really helpful when diagnosing crash causes from crash reports,
so this is a great improvement. Thank you.

Here is a search that shows all crashes submitted in the past 7 days that
have a 'moz crash reason' field, faceted by that field:

https://crash-stats.mozilla.com/search/?moz_crash_reason=%21__null__&product=Firefox&date=%3E%3D2016-11-03T22%3A35%3A00.000Z&date=%3C2016-11-10T22%3A35%3A00.000Z&_sort=-date&_facets=signature&_facets=moz_crash_reason&_columns=date&_columns=signature&_columns=product&_columns=version&_columns=build_id&_columns=platform#facet-moz_crash_reason

Already some JS-related ones are showing up, e.g. 278 occurrences of
"MOZ_CRASH(Why
is someone touching JSAPI without an AutoJSAPI?)

"

Nick


On Fri, Nov 11, 2016 at 9:06 AM, Emanuel Hoogeveen <
emanuel.hoogeveen@gmail.com> wrote:

> With the landing of bug 1309573 (included in today's Nightly), crash
> reports from intentionally triggered crashes in SpiderMonkey now have a
> 'moz crash reason', which is the reason string or expression from a
> MOZ_CRASH() or failed assertion. This is something that most of core Gecko
> has had access to all along, but it was predicated on both
> MOZILLA_INTERNAL_API and MOZ_CRASHREPORTER - neither of which libjs had
> access to!
>
> The moz crash reason can be useful to understand stacks with heavy
> inlining at a glance, and might help aggregate crash signatures if the
> reason string or expression is unique enough. It can also be used to expose
> dynamic information such as an error code, though MOZ_CRASH() itself only
> works with string literals (several places in Gecko already work around
> this).
>
> As proof that this is working now, here are the first two crash reports
> from crashes in SM with a moz crash reason:
> https://crash-stats.mozilla.com/report/index/2b5360a0-
> a360-4f7f-8402-b07bb2161110
> https://crash-stats.mozilla.com/report/index/f5aca357-
> 47fd-475f-ae51-4c4a82161110
>
> For context, we discovered that the moz crash reason was missing because
> the annotations from bug 1305360 weren't showing up. The protection added
> in that bug generates generic memory protection crashes that are very hard
> to pick out from the crowd without an annotation, so having the moz crash
> reason is essential.
> _______________________________________________
> dev-tech-js-engine-internals mailing list
> dev-tech-js-engine-internals@lists.mozilla.org
> https://lists.mozilla.org/listinfo/dev-tech-js-engine-internals
>