1416602 - Crash in mozalloc_abort | abort | webrender::resource_cache::ResourceCache::update_resources

Status: RESOLVED WORKSFORME

(Core :: Graphics: WebRender, defect, P3)

Description

[Darkspirit]

Seen on Socorro.

The one and only report so far:
bp-a49daf64-91a7-4a3c-a5b0-e0fc90171112 (20171112100435)
> MOZ_CRASH Reason: called `Option::unwrap()` on a `None` value

(Maybe a regression?)

Comment 1

[(not currently active) Ted Mielczarek]

I just hit this locally:
https://crash-stats.mozilla.com/report/index/f8bf3530-aed3-4d07-b3e0-fcde20171206

I had closed a few tabs, realized I needed one of them, so I hit Shift+Ctrl+T several times in quick succession to unclose them and Firefox crashed. Unfortunately the stack isn't super helpful given the Rust compiler's heavy use of inlining + weirdness of debug info for macros, since the frame that panic'ed is just:
 8 	libxul.so	webrender::resource_cache::ResourceCache::update_resources	src/libcore/macros.rs:20 

(that source line is literally the implementation of `panic!` in the standard library.)

It's clearly in here somewhere: https://hg.mozilla.org/mozilla-central/file/79d3e25106f8/gfx/webrender/src/resource_cache.rs#l274

...but I can't tell exactly where. That file does contain a number of calls to `unwrap()`, which doesn't seem great.

Comment 2

[(not currently active) Ted Mielczarek]

I got objdump to disassemble that whole function but it doesn't help much:
https://gist.github.com/luser/3992395fb238238dc4d5fb29711a0d06

The call to panic is here:
_ZN4core6option8{{impl}}46unwrap<&webrender::platform::unix::font::Face>E():
/build/mozilla-central/macros.rs:20
 3c09aa6:	48 8d 3d c3 a3 b5 01 	lea    0x1b5a3c3(%rip),%rdi        # 5763e70 <ref.4K.2926>
3c09aad: e8 1e c6 3a 00 callq 3fb60d0 <core::panicking::panic>

So I guess it's something dealing with fonts, at least?

Comment 3

[Darkspirit]

This combination of crash signature and crash reason hasn't happened anymore.