Kernel: Show more (b)locking info when dumping the process list

Kernel/Scheduler.cpp

@@ -564,6 +564,17 @@ void dump_thread_list(bool with_stack_traces)
                 thread.times_scheduled());
             break;
         }
+        if (thread.state() == Thread::State::Blocked && thread.blocking_mutex()) {
+            dmesgln("    Blocking on Mutex {:#x} ({})", thread.blocking_mutex(), thread.blocking_mutex()->name());
+        }
+        if (thread.state() == Thread::State::Blocked && thread.blocker()) {
+            dmesgln("    Blocking on Blocker {:#x}", thread.blocker());
+        }
+#if LOCK_DEBUG
+        thread.for_each_held_lock([](auto const& entry) {
+            dmesgln("    Holding lock {:#x} ({}) at {}", entry.lock, entry.lock->name(), entry.lock_location);
+        });
+#endif
         if (with_stack_traces) {
             auto trace_or_error = thread.backtrace();
             if (!trace_or_error.is_error()) {

Kernel/Thread.h

@@ -1154,6 +1154,22 @@ public:
 
     ErrorOr<NonnullOwnPtr<KString>> backtrace();
 
+    Blocker const* blocker() const { return m_blocker; };
+    Kernel::Mutex const* blocking_mutex() const { return m_blocking_mutex; }
+
+#if LOCK_DEBUG
+    struct HoldingLockInfo {
+        Mutex* lock;
+        LockLocation lock_location;
+        unsigned count;
+    };
+
+    template<IteratorFunction<HoldingLockInfo const&> Callback>
+    void for_each_held_lock(Callback);
+    template<VoidFunction<HoldingLockInfo const&> Callback>
+    void for_each_held_lock(Callback);
+#endif
+
 private:
     Thread(NonnullLockRefPtr<Process>, NonnullOwnPtr<Memory::Region>, NonnullLockRefPtr<Timer>, NonnullOwnPtr<KString>);
 
@@ -1266,11 +1282,6 @@ private:
     IntrusiveListNode<Thread> m_big_lock_blocked_threads_list_node;
 
 #if LOCK_DEBUG
-    struct HoldingLockInfo {
-        Mutex* lock;
-        LockLocation lock_location;
-        unsigned count;
-    };
     Atomic<u32> m_holding_locks { 0 };
     Spinlock m_holding_locks_lock { LockRank::None };
     Vector<HoldingLockInfo> m_holding_locks_list;
@@ -1386,6 +1397,28 @@ inline IterationDecision Thread::for_each_in_state(State state, Callback callbac
     });
 }
 
+#if LOCK_DEBUG
+template<IteratorFunction<Thread::HoldingLockInfo const&> Callback>
+inline void Thread::for_each_held_lock(Callback callback)
+{
+    SpinlockLocker list_lock(m_holding_locks_lock);
+
+    for (auto const& lock_info : m_holding_locks_list) {
+        if (callback(lock_info) == IterationDecision::Break)
+            break;
+    }
+}
+
+template<VoidFunction<Thread::HoldingLockInfo const&> Callback>
+inline void Thread::for_each_held_lock(Callback callback)
+{
+    for_each_held_lock([&](auto const& lock_info) {
+        callback(lock_info);
+        return IterationDecision::Continue;
+    });
+}
+#endif
+
 }
 
 template<>