[scudo] Don't unmap other low memory pages if mapping doesn't exist

Tests can register multiple allocators, but only the first will initialize since it initializes the TSDRegistrySharedT. Then, destruction of subsequent allocator may end up unmapping a nullptr PrimaryBase with non-zero PrimarySize.

Differential Revision: https://reviews.llvm.org/D121858

diff --git a/compiler-rt/lib/scudo/standalone/primary64.h b/compiler-rt/lib/scudo/standalone/primary64.h
index 6c17855..14784ee 100644 (file)
--- a/compiler-rt/lib/scudo/standalone/primary64.h
+++ b/compiler-rt/lib/scudo/standalone/primary64.h
@@ -89,7 +89,9 @@ public:
       RegionInfo *Region = getRegionInfo(I);
       *Region = {};
     }
-    unmap(reinterpret_cast<void *>(PrimaryBase), PrimarySize, UNMAP_ALL, &Data);
+    if (PrimaryBase)
+      unmap(reinterpret_cast<void *>(PrimaryBase), PrimarySize, UNMAP_ALL,
+            &Data);
     PrimaryBase = 0U;
   }