Kernel: Allow adding signals to thread that are blocked

kernel/include/kernel/Thread.h

@@ -59,7 +59,7 @@ namespace Kernel
 		bool will_execute_signal() const;
 		// Returns true if handled signal had SA_RESTART
 		bool handle_signal(int signal = 0);
-		bool add_signal(int signal);
+		void add_signal(int signal);
 
 		// blocks current thread and returns either on unblock, eintr, spuriously or after timeout
 		// if mutex is not nullptr, it will be atomically freed before blocking and automatically locked on wake

kernel/kernel/Process.cpp

@@ -309,7 +309,7 @@ namespace Kernel
 			LockGuard _(m_process_lock);
 			for (auto* thread : m_threads)
 				if (thread != &Thread::current())
-					ASSERT(thread->add_signal(SIGKILL));
+					thread->add_signal(SIGKILL);
 		}
 
 		while (m_threads.size() > 1)

kernel/kernel/Thread.cpp

@@ -619,7 +619,7 @@ namespace Kernel
 		return has_sa_restart;
 	}
 
-	bool Thread::add_signal(int signal)
+	void Thread::add_signal(int signal)
 	{
 		SpinLockGuard _(m_signal_lock);
 		if (m_process)
@@ -631,19 +631,16 @@ namespace Kernel
 				signal_handler = (vaddr_t)m_process->m_signal_handlers[signal].sa_handler;
 			}
 			if (signal_handler == (vaddr_t)SIG_IGN)
-				return false;
+				return;
 			if (signal_handler == (vaddr_t)SIG_DFL && is_default_ignored_signal(signal))
-				return false;
+				return;
 		}
-		uint64_t mask = 1ull << signal;
-		if (!(m_signal_block_mask & mask))
-		{
+
+		const uint64_t mask = 1ull << signal;
 		m_signal_pending_mask |= mask;
+
 		if (this != &Thread::current())
 			Processor::scheduler().unblock_thread(this);
-			return true;
-		}
-		return false;
 	}
 
 	BAN::ErrorOr<void> Thread::sleep_or_eintr_ns(uint64_t ns)