491023 - Arena allocations in LeaveTree aren't really infallible

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Jason Orendorff [:jorendorff]]

Graydon pointed this out a week or two ago.  The strategy here is

1. When entering a trace, allocate a big chunk of memory.
2. Make sure we only ever need that much memory when leaving trace.
3. In LeaveTree, RELEASE that memory all at once, and
4. ALLOCATE it in smaller chunks for stack frames.

The big chunk is always on a single page.  But RELEASE could give that page back to the OS, so the following ALLOCATE could fail.

Comment 1

[Ryan VanderMeulen [:RyanVM]]

Obsolete with the removal of tracejit.