1927663 - MOZ_RELEASE_ASSERT(disabledHugeMemory) when setting javascript.options.wasm_disable_huge_memory=true

Status: NEW

(Core :: JavaScript: WebAssembly, defect, P3)

Description

[Mike Hommey [:glandium]]

Crash report on a nightly: https://crash-stats.mozilla.org/report/index/b2299b52-87ca-4fb5-a176-41cc90241029

STR:

• open about:config
• add a javascript.options.wasm_disable_huge_memory boolean pref and set it to true
• restart Firefox

Result:

• crash on startup. Can't be fixed until the pref is removed by editing the prefs.js file manually.

Comment 1

[Matthew Gaudet (he/him) [:mgaudet]]

Hey, this seems... maybe up your alley?

Comment 2

[Ryan Hunt [:rhunt]]

Yeah, it is.

Comment 3

[Ryan Hunt [:rhunt]]

Attachment: Bug 1927663 - wasm: Refactor handling of 'disable_huge_memory'. r?bvisness

The old system required wasm::DisableHugeMemory() to be called
before anyone calls wasm::HugeMemoryEnabled(), and enforced that with
some runtime checks.

We had a bug where GetOptimizedBuildEncodingId() (which queries the
huge memory flag) would be called by Gecko before we read the pref.

This commit refactors this code to use a JS::Pref instead which is
always set before JS_Init() is invoked. This ensures that it is
never changed after we've observed the value and can drop all the
fancy runtime checking.