Print stacktrace when asserting a lock is held

src/sync.cpp

@@ -25,6 +25,10 @@
 #include <boost/foreach.hpp>
 #include <boost/thread.hpp>
 
+#include <execinfo.h> /* backtrace, backtrace_symbols_fd */
+#include <unistd.h> /* STDOUT_FILENO */
+
+
 #ifdef DEBUG_LOCKCONTENTION
 void PrintLockContention(const char* pszName, const char* pszFile, int nLine)
 {
@@ -177,12 +181,23 @@ std::string LocksHeld()
     return result;
 }
 
+void print_stacktrace(void) {
+    size_t size;
+    enum Constexpr { MAX_SIZE = 1024 };
+    void *array[MAX_SIZE];
+    size = backtrace(array, MAX_SIZE);
+    backtrace_symbols_fd(array, size, STDERR_FILENO);
+}
+
 void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs)
 {
     BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, *lockstack)
         if (i.first == cs)
             return;
     fprintf(stderr, "Assertion failed: lock %s not held in %s:%i; locks held:\n%s", pszName, pszFile, nLine, LocksHeld().c_str());
+
+    print_stacktrace();
+
     abort();
 }