Mangle the pointers stored in PointerData.
The libmemunreachable library looks through memory to determine
if pointers are leaked. Unfortunately, the malloc debug code
stores the original pointer in data structures, so it looks like
pointers are still in use. The fix is to mangle the pointers
stored in memory so that it doesn't trick the library into thinking
they are live.
Test: All unit/system tests pass.
Test: Ran libmemunreachable and verified leaks show up.
Change-Id: Ic40a0a5ae73857cde936fd76895d88829686a643
diff --git a/libc/malloc_debug/PointerData.h b/libc/malloc_debug/PointerData.h
index 92d2653..97eec0a 100644
--- a/libc/malloc_debug/PointerData.h
+++ b/libc/malloc_debug/PointerData.h
@@ -33,6 +33,7 @@
#include <atomic>
#include <deque>
+#include <functional>
#include <mutex>
#include <string>
#include <unordered_map>
@@ -99,7 +100,7 @@
};
struct FreePointerInfoType {
- uintptr_t pointer;
+ uintptr_t mangled_ptr;
size_t hash_index;
};
@@ -134,16 +135,14 @@
void PostForkParent();
void PostForkChild();
+ static void IteratePointers(std::function<void(uintptr_t pointer)> fn);
+
static size_t AddBacktrace(size_t num_frames);
static void RemoveBacktrace(size_t hash_index);
static void Add(const void* pointer, size_t size);
static void Remove(const void* pointer);
- typedef std::unordered_map<uintptr_t, PointerInfoType>::iterator iterator;
- static iterator begin() { return pointers_.begin(); }
- static iterator end() { return pointers_.end(); }
-
static void* AddFreed(const void* pointer);
static void LogFreeError(const FreePointerInfoType& info, size_t usable_size);
static void LogFreeBacktrace(const void* ptr);
@@ -162,6 +161,12 @@
static bool Exists(const void* pointer);
private:
+ // Only keep mangled pointers in internal data structures. This avoids
+ // problems where libmemunreachable finds these pointers and thinks they
+ // are not unreachable.
+ static inline uintptr_t ManglePointer(uintptr_t pointer) { return pointer ^ UINTPTR_MAX; }
+ static inline uintptr_t DemanglePointer(uintptr_t pointer) { return pointer ^ UINTPTR_MAX; }
+
static std::string GetHashString(uintptr_t* frames, size_t num_frames);
static void LogBacktrace(size_t hash_index);