Merge "Prepare to fail in RefBase destructor if count is untouched"
am: f502182ac6
Change-Id: I91ff7140a9a72c910ef01a2e13f277fa36c82b50
diff --git a/libbacktrace/include/backtrace/BacktraceMap.h b/libbacktrace/include/backtrace/BacktraceMap.h
index a9cfce4..c564271 100644
--- a/libbacktrace/include/backtrace/BacktraceMap.h
+++ b/libbacktrace/include/backtrace/BacktraceMap.h
@@ -31,6 +31,7 @@
#include <deque>
#include <iterator>
+#include <memory>
#include <string>
#include <vector>
diff --git a/libutils/CallStack.cpp b/libutils/CallStack.cpp
index bd6015e..2a83bd9 100644
--- a/libutils/CallStack.cpp
+++ b/libutils/CallStack.cpp
@@ -16,16 +16,15 @@
#define LOG_TAG "CallStack"
-#include <utils/CallStack.h>
-
-#include <memory>
-
#include <utils/Printer.h>
#include <utils/Errors.h>
#include <utils/Log.h>
#include <backtrace/Backtrace.h>
+#define CALLSTACK_WEAK // Don't generate weak definitions.
+#include <utils/CallStack.h>
+
namespace android {
CallStack::CallStack() {
@@ -76,4 +75,26 @@
}
}
+// The following four functions may be used via weak symbol references from libutils.
+// Clients assume that if any of these symbols are available, then deleteStack() is.
+
+CallStack::CallStackUPtr CallStack::getCurrentInternal(int ignoreDepth) {
+ CallStack::CallStackUPtr stack(new CallStack());
+ stack->update(ignoreDepth + 1);
+ return stack;
+}
+
+void CallStack::logStackInternal(const char* logtag, const CallStack* stack,
+ android_LogPriority priority) {
+ stack->log(logtag, priority);
+}
+
+String8 CallStack::stackToStringInternal(const char* prefix, const CallStack* stack) {
+ return stack->toString(prefix);
+}
+
+void CallStack::deleteStack(CallStack* stack) {
+ delete stack;
+}
+
}; // namespace android
diff --git a/libutils/RefBase.cpp b/libutils/RefBase.cpp
index 9074850..3f1e79a 100644
--- a/libutils/RefBase.cpp
+++ b/libutils/RefBase.cpp
@@ -17,30 +17,41 @@
#define LOG_TAG "RefBase"
// #define LOG_NDEBUG 0
+#include <memory>
+
#include <utils/RefBase.h>
#include <utils/CallStack.h>
+#include <utils/Mutex.h>
+
#ifndef __unused
#define __unused __attribute__((__unused__))
#endif
-// compile with refcounting debugging enabled
-#define DEBUG_REFS 0
+// Compile with refcounting debugging enabled.
+#define DEBUG_REFS 0
+
+// The following three are ignored unless DEBUG_REFS is set.
// whether ref-tracking is enabled by default, if not, trackMe(true, false)
// needs to be called explicitly
-#define DEBUG_REFS_ENABLED_BY_DEFAULT 0
+#define DEBUG_REFS_ENABLED_BY_DEFAULT 0
// whether callstack are collected (significantly slows things down)
-#define DEBUG_REFS_CALLSTACK_ENABLED 1
+#define DEBUG_REFS_CALLSTACK_ENABLED 1
// folder where stack traces are saved when DEBUG_REFS is enabled
// this folder needs to exist and be writable
-#define DEBUG_REFS_CALLSTACK_PATH "/data/debug"
+#define DEBUG_REFS_CALLSTACK_PATH "/data/debug"
// log all reference counting operations
-#define PRINT_REFS 0
+#define PRINT_REFS 0
+
+// Continue after logging a stack trace if ~RefBase discovers that reference
+// count has never been incremented. Normally we conspicuously crash in that
+// case.
+#define DEBUG_REFBASE_DESTRUCTION 1
// ---------------------------------------------------------------------------
@@ -184,7 +195,7 @@
char inc = refs->ref >= 0 ? '+' : '-';
ALOGD("\t%c ID %p (ref %d):", inc, refs->id, refs->ref);
#if DEBUG_REFS_CALLSTACK_ENABLED
- refs->stack.log(LOG_TAG);
+ CallStack::logStack(LOG_TAG, refs->stack.get());
#endif
refs = refs->next;
}
@@ -198,14 +209,14 @@
char inc = refs->ref >= 0 ? '+' : '-';
ALOGD("\t%c ID %p (ref %d):", inc, refs->id, refs->ref);
#if DEBUG_REFS_CALLSTACK_ENABLED
- refs->stack.log(LOG_TAG);
+ CallStack::logStack(LOG_TAG, refs->stack.get());
#endif
refs = refs->next;
}
}
if (dumpStack) {
ALOGE("above errors at:");
- CallStack stack(LOG_TAG);
+ CallStack::logStack(LOG_TAG);
}
}
@@ -279,7 +290,7 @@
this);
int rc = open(name, O_RDWR | O_CREAT | O_APPEND, 644);
if (rc >= 0) {
- write(rc, text.string(), text.length());
+ (void)write(rc, text.string(), text.length());
close(rc);
ALOGD("STACK TRACE for %p saved in %s", this, name);
}
@@ -294,7 +305,7 @@
ref_entry* next;
const void* id;
#if DEBUG_REFS_CALLSTACK_ENABLED
- CallStack stack;
+ CallStack::CallStackUPtr stack;
#endif
int32_t ref;
};
@@ -311,7 +322,7 @@
ref->ref = mRef;
ref->id = id;
#if DEBUG_REFS_CALLSTACK_ENABLED
- ref->stack.update(2);
+ ref->stack = CallStack::getCurrent(2);
#endif
ref->next = *refs;
*refs = ref;
@@ -346,7 +357,7 @@
ref = ref->next;
}
- CallStack stack(LOG_TAG);
+ CallStack::logStack(LOG_TAG);
}
}
@@ -373,7 +384,7 @@
inc, refs->id, refs->ref);
out->append(buf);
#if DEBUG_REFS_CALLSTACK_ENABLED
- out->append(refs->stack.toString("\t\t"));
+ out->append(CallStack::stackToString("\t\t", refs->stack.get()));
#else
out->append("\t\t(call stacks disabled)");
#endif
@@ -700,16 +711,16 @@
if (mRefs->mWeak.load(std::memory_order_relaxed) == 0) {
delete mRefs;
}
- } else if (mRefs->mStrong.load(std::memory_order_relaxed)
- == INITIAL_STRONG_VALUE) {
+ } else if (mRefs->mStrong.load(std::memory_order_relaxed) == INITIAL_STRONG_VALUE) {
// We never acquired a strong reference on this object.
- LOG_ALWAYS_FATAL_IF(mRefs->mWeak.load() != 0,
- "RefBase: Explicit destruction with non-zero weak "
- "reference count");
- // TODO: Always report if we get here. Currently MediaMetadataRetriever
- // C++ objects are inconsistently managed and sometimes get here.
- // There may be other cases, but we believe they should all be fixed.
- delete mRefs;
+#if DEBUG_REFBASE_DESTRUCTION
+ // Treating this as fatal is prone to causing boot loops. For debugging, it's
+ // better to treat as non-fatal.
+ ALOGD("RefBase: Explicit destruction, weak count = %d (in %p)", mRefs->mWeak.load(), this);
+ CallStack::logStack(LOG_TAG);
+#else
+ LOG_ALWAYS_FATAL("RefBase: Explicit destruction, weak count = %d", mRefs->mWeak.load());
+#endif
}
// For debugging purposes, clear mRefs. Ineffective against outstanding wp's.
const_cast<weakref_impl*&>(mRefs) = nullptr;
diff --git a/libutils/include/utils/CallStack.h b/libutils/include/utils/CallStack.h
index 0c1b875..a7b1d10 100644
--- a/libutils/include/utils/CallStack.h
+++ b/libutils/include/utils/CallStack.h
@@ -17,6 +17,8 @@
#ifndef ANDROID_CALLSTACK_H
#define ANDROID_CALLSTACK_H
+#include <memory>
+
#include <android/log.h>
#include <backtrace/backtrace_constants.h>
#include <utils/String8.h>
@@ -25,6 +27,11 @@
#include <stdint.h>
#include <sys/types.h>
+#ifndef CALLSTACK_WEAK
+#define CALLSTACK_WEAK __attribute__((weak))
+#endif
+#define ALWAYS_INLINE __attribute__((always_inline))
+
namespace android {
class Printer;
@@ -36,7 +43,7 @@
CallStack();
// Create a callstack with the current thread's stack trace.
// Immediately dump it to logcat using the given logtag.
- CallStack(const char* logtag, int32_t ignoreDepth=1);
+ CallStack(const char* logtag, int32_t ignoreDepth = 1);
~CallStack();
// Reset the stack frames (same as creating an empty call stack).
@@ -44,7 +51,7 @@
// Immediately collect the stack traces for the specified thread.
// The default is to dump the stack of the current call.
- void update(int32_t ignoreDepth=1, pid_t tid=BACKTRACE_CURRENT_THREAD);
+ void update(int32_t ignoreDepth = 1, pid_t tid = BACKTRACE_CURRENT_THREAD);
// Dump a stack trace to the log using the supplied logtag.
void log(const char* logtag,
@@ -63,7 +70,58 @@
// Get the count of stack frames that are in this call stack.
size_t size() const { return mFrameLines.size(); }
-private:
+ // DO NOT USE ANYTHING BELOW HERE. The following public members are expected
+ // to disappear again shortly, once a better replacement facility exists.
+ // The replacement facility will be incompatible!
+
+ // Debugging accesses to some basic functionality. These use weak symbols to
+ // avoid introducing a dependency on libutilscallstack. Such a dependency from
+ // libutils results in a cyclic build dependency. These routines can be called
+ // from within libutils. But if the actual library is unavailable, they do
+ // nothing.
+ //
+ // DO NOT USE THESE. They will disappear.
+ struct StackDeleter {
+ void operator()(CallStack* stack) { deleteStack(stack); }
+ };
+
+ typedef std::unique_ptr<CallStack, StackDeleter> CallStackUPtr;
+
+ // Return current call stack if possible, nullptr otherwise.
+ static CallStackUPtr ALWAYS_INLINE getCurrent(int32_t ignoreDepth = 1) {
+ if (reinterpret_cast<uintptr_t>(getCurrentInternal) == 0) {
+ ALOGW("CallStack::getCurrentInternal not linked, returning null");
+ return CallStackUPtr(nullptr);
+ } else {
+ return getCurrentInternal(ignoreDepth);
+ }
+ }
+ static void ALWAYS_INLINE logStack(const char* logtag, CallStack* stack = getCurrent().get(),
+ android_LogPriority priority = ANDROID_LOG_DEBUG) {
+ if (reinterpret_cast<uintptr_t>(logStackInternal) != 0 && stack != nullptr) {
+ logStackInternal(logtag, stack, priority);
+ } else {
+ ALOGW("CallStack::logStackInternal not linked");
+ }
+ }
+ static String8 ALWAYS_INLINE stackToString(const char* prefix = nullptr,
+ const CallStack* stack = getCurrent().get()) {
+ if (reinterpret_cast<uintptr_t>(stackToStringInternal) != 0 && stack != nullptr) {
+ return stackToStringInternal(prefix, stack);
+ } else {
+ return String8("<CallStack package not linked>");
+ }
+ }
+
+ private:
+ static CallStackUPtr CALLSTACK_WEAK getCurrentInternal(int32_t ignoreDepth);
+ static void CALLSTACK_WEAK logStackInternal(const char* logtag, const CallStack* stack,
+ android_LogPriority priority);
+ static String8 CALLSTACK_WEAK stackToStringInternal(const char* prefix, const CallStack* stack);
+ // The deleter is only invoked on non-null pointers. Hence it will never be
+ // invoked if CallStack is not linked.
+ static void CALLSTACK_WEAK deleteStack(CallStack* stack);
+
Vector<String8> mFrameLines;
};