[PATCH] D69675: [scudo][standalone] Fix Secondary bug w/ freelist

[Kostya Kortchinsky via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGc7bc3db23caf: [scudo][standalone] Fix Secondary bug w/ freelist (authored by cryptoad).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D69675/new/

https://reviews.llvm.org/D69675

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


Index: compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
===================================================================
--- compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
+++ compiler-rt/lib/scudo/standalone/tests/combined_test.cpp
@@ -65,6 +65,20 @@
   }
   Allocator->releaseToOS();
 
+  // Ensure that specifying ZeroContents returns a zero'd out block.
+  for (scudo::uptr SizeLog = 0U; SizeLog <= 20U; SizeLog++) {
+    for (scudo::uptr Delta = 0U; Delta <= 4U; Delta++) {
+      const scudo::uptr Size = (1U << SizeLog) + Delta * 128U;
+      void *P = Allocator->allocate(Size, Origin, 1U << MinAlignLog, true);
+      EXPECT_NE(P, nullptr);
+      for (scudo::uptr I = 0; I < Size; I++)
+        EXPECT_EQ((reinterpret_cast<char *>(P))[I], 0);
+      memset(P, 0xaa, Size);
+      Allocator->deallocate(P, Origin, Size);
+    }
+  }
+  Allocator->releaseToOS();
+
   // Verify that a chunk will end up being reused, at some point.
   const scudo::uptr NeedleSize = 1024U;
   void *NeedleP = Allocator->allocate(NeedleSize, Origin);
Index: compiler-rt/lib/scudo/standalone/secondary.h
===================================================================
--- compiler-rt/lib/scudo/standalone/secondary.h
+++ compiler-rt/lib/scudo/standalone/secondary.h
@@ -60,7 +60,8 @@
     initLinkerInitialized(S);
   }
 
-  void *allocate(uptr Size, uptr AlignmentHint = 0, uptr *BlockEnd = nullptr);
+  void *allocate(uptr Size, uptr AlignmentHint = 0, uptr *BlockEnd = nullptr,
+                 bool ZeroContents = false);
 
   void deallocate(void *Ptr);
 
@@ -111,7 +112,8 @@
 // (pending rounding and headers).
 template <uptr MaxFreeListSize>
 void *MapAllocator<MaxFreeListSize>::allocate(uptr Size, uptr AlignmentHint,
-                                              uptr *BlockEnd) {
+                                              uptr *BlockEnd,
+                                              bool ZeroContents) {
   DCHECK_GT(Size, AlignmentHint);
   const uptr PageSize = getPageSizeCached();
   const uptr RoundedSize =
@@ -133,8 +135,11 @@
       Stats.add(StatAllocated, FreeBlockSize);
       if (BlockEnd)
         *BlockEnd = H.BlockEnd;
-      return reinterpret_cast<void *>(reinterpret_cast<uptr>(&H) +
-                                      LargeBlock::getHeaderSize());
+      void *Ptr = reinterpret_cast<void *>(reinterpret_cast<uptr>(&H) +
+                                           LargeBlock::getHeaderSize());
+      if (ZeroContents)
+        memset(Ptr, 0, H.BlockEnd - reinterpret_cast<uptr>(Ptr));
+      return Ptr;
     }
   }
 
Index: compiler-rt/lib/scudo/standalone/combined.h
===================================================================
--- compiler-rt/lib/scudo/standalone/combined.h
+++ compiler-rt/lib/scudo/standalone/combined.h
@@ -161,6 +161,7 @@
                           uptr Alignment = MinAlignment,
                           bool ZeroContents = false) {
     initThreadMaybe();
+    ZeroContents = ZeroContents || Options.ZeroContents;
 
     if (UNLIKELY(Alignment > MaxAlignment)) {
       if (Options.MayReturnNull)
@@ -200,7 +201,8 @@
         TSD->unlock();
     } else {
       ClassId = 0;
-      Block = Secondary.allocate(NeededSize, Alignment, &BlockEnd);
+      Block =
+          Secondary.allocate(NeededSize, Alignment, &BlockEnd, ZeroContents);
     }
 
     if (UNLIKELY(!Block)) {
@@ -212,7 +214,7 @@
     // We only need to zero the contents for Primary backed allocations. This
     // condition is not necessarily unlikely, but since memset is costly, we
     // might as well mark it as such.
-    if (UNLIKELY((ZeroContents || Options.ZeroContents) && ClassId))
+    if (UNLIKELY(ZeroContents && ClassId))
       memset(Block, 0, PrimaryT::getSizeByClassId(ClassId));
 
     Chunk::UnpackedHeader Header = {};


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