Jason Orendorff [:jorendorff] Reporter
	Description • 15 years ago

Here's the scenario:

  - Thread 2 calls js_GC with GC_SET_SLOT_REQUEST. It skips the GC callback,
    nudges all threads, and waits for them to quiesce.

  - Thread 1 calls js_GC with GC_NORMAL. It calls the GC callback, then
    ends up in the code that decrements rt->requestCount and waits for GC to
    finish.

  - Thread 2 processes JSSetSlotRequests, then notes that GC is needed and
    does 'goto restart_at_beginning'.

  - Thread 2 calls the GC callback, which vetoes GC. Thread 2 calls
    JS_NOTIFY_GC_DONE. Both threads return from js_GC. GC has not happened.

This can happen in Gecko if thread 1 is the main thread.