ensure that uint subtractions doesn't accidentially underflow

JuliaLang · Oct 6, 2023 · 42f291d · 42f291d
1 parent 8380784
commit 42f291d
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/src/gc.c b/src/gc.c
@@ -1188,7 +1188,8 @@ static void combine_thread_gc_counts(jl_gc_num_t *dest) JL_NOTSAFEPOINT
  uint64_t alloc_acc = jl_atomic_load_relaxed(&ptls->gc_num.alloc_acc);
  uint64_t free_acc = jl_atomic_load_relaxed(&ptls->gc_num.free_acc);
  dest->freed += jl_atomic_load_relaxed(&ptls->gc_num.free_acc);
- jl_atomic_store_relaxed(&gc_heap_stats.heap_size, alloc_acc - free_acc + jl_atomic_load_relaxed(&gc_heap_stats.heap_size));
+ int64_t diff = alloc_acc - free_acc;
+ jl_atomic_store_relaxed(&gc_heap_stats.heap_size, diff + jl_atomic_load_relaxed(&gc_heap_stats.heap_size));
  jl_atomic_store_relaxed(&ptls->gc_num.alloc_acc, 0);
  jl_atomic_store_relaxed(&ptls->gc_num.free_acc, 0);
  }