Prevent the GC task callback from segfaulting. (JuliaLang#32088)

It is possible when marking task objects in the GC for the associated jl_ptls_t reference to be NULL. To determine whether a task is a root task, we therefore also have to check if that reference is valid.
halleysfifthinc · May 20, 2019 · 25c33e4 · 25c33e4
1 parent b238945
commit 25c33e4
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/src/gc.c b/src/gc.c
@@ -2344,7 +2344,8 @@ mark: {
  if (gc_cblist_task_scanner) {
  export_gc_state(ptls, &sp);
  gc_invoke_callbacks(jl_gc_cb_task_scanner_t,
- gc_cblist_task_scanner, (ta, ta == ptls2->root_task));
+ gc_cblist_task_scanner,
+ (ta, ptls2 != NULL && ta == ptls2->root_task));
  import_gc_state(ptls, &sp);
  }
 #ifdef COPY_STACKS