[compiler-rt] 15664fe - [scudo][standalone] Fix for releaseToOS prior to init

[Kostya Kortchinsky via llvm-commits]

Author: Kostya Kortchinsky
Date: 2019-11-25T08:38:45-08:00
New Revision: 15664fe2c48be242b4b38422466246e9592b6670

URL: https://github.com/llvm/llvm-project/commit/15664fe2c48be242b4b38422466246e9592b6670
DIFF: https://github.com/llvm/llvm-project/commit/15664fe2c48be242b4b38422466246e9592b6670.diff

LOG: [scudo][standalone] Fix for releaseToOS prior to init

Summary:
cferris@ found an issue where calling `releaseToOS` prior to any other
heap operation would lead to a crash, due to the allocator not being
properly initialized (it was discovered via `mallopt`).

The fix is to call `initThreadMaybe` prior to calling `releaseToOS` for
the Primary.

Add a test that crashes prior to fix.

Reviewers: hctim, cferris, pcc, eugenis

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D70552

Added: 
    

Modified: 
    compiler-rt/lib/scudo/standalone/combined.h
    compiler-rt/lib/scudo/standalone/tests/combined_test.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/scudo/standalone/combined.h b/compiler-rt/lib/scudo/standalone/combined.h
index 0a05857a20d6..8560c2d3599f 100644
--- a/compiler-rt/lib/scudo/standalone/combined.h
+++ b/compiler-rt/lib/scudo/standalone/combined.h
@@ -402,7 +402,10 @@ template <class Params> class Allocator {
     Str.output();
   }
 
-  void releaseToOS() { Primary.releaseToOS(); }
+  void releaseToOS() {
+    initThreadMaybe();
+    Primary.releaseToOS();
+  }
 
   // Iterate over all chunks and call a callback for all busy chunks located
   // within the provided memory range. Said callback must not use this allocator

diff  --git a/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp b/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
index d32ea89e0ea3..9205467998ed 100644
--- a/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
@@ -279,3 +279,18 @@ TEST(ScudoCombinedTest, DeathCombined) {
   EXPECT_DEATH(Allocator->reallocate(P, Size * 2U), "");
   EXPECT_DEATH(Allocator->getUsableSize(P), "");
 }
+
+// Ensure that releaseToOS can be called prior to any other allocator
+// operation without issue.
+TEST(ScudoCombinedTest, ReleaseToOS) {
+  using AllocatorT = scudo::Allocator<DeathConfig>;
+  auto Deleter = [](AllocatorT *A) {
+    A->unmapTestOnly();
+    delete A;
+  };
+  std::unique_ptr<AllocatorT, decltype(Deleter)> Allocator(new AllocatorT,
+                                                           Deleter);
+  Allocator->reset();
+
+  Allocator->releaseToOS();
+}