From 6e95519accff23b120b3b5b46fec32e55395f9d6 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Sat, 16 May 2026 23:52:28 +0300
Subject: [PATCH] Kernel: Make TTY write lock a mutex instead of a spinlock

The mutex could not be locked while processing ANSI DGR in VTTY
---
 kernel/include/kernel/Terminal/TTY.h  |  2 +-
 kernel/kernel/Terminal/TTY.cpp        | 10 ++++------
 kernel/kernel/Terminal/VirtualTTY.cpp | 18 +++++++++---------
 3 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/kernel/include/kernel/Terminal/TTY.h b/kernel/include/kernel/Terminal/TTY.h
index 42d23332..74943048 100644
--- a/kernel/include/kernel/Terminal/TTY.h
+++ b/kernel/include/kernel/Terminal/TTY.h
@@ -105,7 +105,7 @@ namespace Kernel
 	protected:
 		Mutex m_mutex;
 
-		RecursiveSpinLock m_write_lock;
+		Mutex m_write_lock;
 		ThreadBlocker m_write_blocker;
 	};
 
diff --git a/kernel/kernel/Terminal/TTY.cpp b/kernel/kernel/Terminal/TTY.cpp
index a4d89068..00b3ee49 100644
--- a/kernel/kernel/Terminal/TTY.cpp
+++ b/kernel/kernel/Terminal/TTY.cpp
@@ -424,7 +424,7 @@ namespace Kernel
 
 		const auto termios = get_termios();
 
-		SpinLockGuard _1(m_write_lock);
+		LockGuard _(m_write_lock);
 		if (termios.c_oflag & OPOST)
 		{
 			if ((termios.c_oflag & ONLCR) && ch == NL)
@@ -471,15 +471,13 @@ namespace Kernel
 
 	BAN::ErrorOr<size_t> TTY::write_impl(off_t, BAN::ConstByteSpan buffer)
 	{
-		SpinLockGuard write_guard(m_write_lock);
+		LockGuard write_guard(m_write_lock);
 
 		while (!can_write())
 		{
 			if (master_has_closed())
 				return BAN::Error::from_errno(EIO);
-
-			SpinLockGuardAsMutex smutex(write_guard);
-			TRY(Thread::current().block_or_eintr_indefinite(m_write_blocker, &smutex));
+			TRY(Thread::current().block_or_eintr_indefinite(m_write_blocker, &m_write_lock));
 		}
 
 		size_t written = 0;
@@ -497,7 +495,7 @@ namespace Kernel
 	void TTY::putchar_current(uint8_t ch)
 	{
 		ASSERT(s_tty);
-		SpinLockGuard _(s_tty->m_write_lock);
+		LockGuard _(s_tty->m_write_lock);
 		s_tty->putchar(ch);
 		s_tty->after_write();
 	}
diff --git a/kernel/kernel/Terminal/VirtualTTY.cpp b/kernel/kernel/Terminal/VirtualTTY.cpp
index 713c29b7..a5999f97 100644
--- a/kernel/kernel/Terminal/VirtualTTY.cpp
+++ b/kernel/kernel/Terminal/VirtualTTY.cpp
@@ -61,7 +61,7 @@ namespace Kernel
 
 	void VirtualTTY::clear()
 	{
-		SpinLockGuard _(m_write_lock);
+		LockGuard _(m_write_lock);
 		for (uint32_t i = 0; i < m_width * m_height; i++)
 			m_buffer[i] = { .foreground = m_foreground, .background = m_background, .codepoint = ' ' };
 		m_terminal_driver->clear(m_background);
@@ -73,7 +73,7 @@ namespace Kernel
 			return BAN::Error::from_errno(EINVAL);
 
 		{
-			SpinLockGuard _(m_write_lock);
+			LockGuard _(m_write_lock);
 
 			TRY(m_terminal_driver->set_font(BAN::move(font)));
 
@@ -110,7 +110,7 @@ namespace Kernel
 
 	void VirtualTTY::reset_ansi()
 	{
-		ASSERT(m_write_lock.current_processor_has_lock());
+		ASSERT(m_write_lock.is_locked_by_current_thread());
 		m_ansi_state = {
 			.nums = { -1, -1, -1, -1, -1 },
 			.index = 0,
@@ -121,7 +121,7 @@ namespace Kernel
 
 	void VirtualTTY::handle_ansi_csi_color(uint8_t value)
 	{
-		ASSERT(m_write_lock.current_processor_has_lock());
+		ASSERT(m_write_lock.is_locked_by_current_thread());
 		switch (value)
 		{
 			case 0:
@@ -201,7 +201,7 @@ namespace Kernel
 
 	void VirtualTTY::handle_ansi_csi(uint8_t ch)
 	{
-		ASSERT(m_write_lock.current_processor_has_lock());
+		ASSERT(m_write_lock.is_locked_by_current_thread());
 		switch (ch)
 		{
 			case '0': case '1': case '2': case '3': case '4':
@@ -446,7 +446,7 @@ namespace Kernel
 
 	void VirtualTTY::render_from_buffer(uint32_t x, uint32_t y)
 	{
-		ASSERT(m_write_lock.current_processor_has_lock());
+		ASSERT(m_write_lock.is_locked_by_current_thread());
 		ASSERT(x < m_width && y < m_height);
 		const auto& cell = m_buffer[y * m_width + x];
 		m_terminal_driver->putchar_at(cell.codepoint, x, y, cell.foreground, cell.background);
@@ -454,7 +454,7 @@ namespace Kernel
 
 	void VirtualTTY::putchar_at(uint32_t codepoint, uint32_t x, uint32_t y)
 	{
-		ASSERT(m_write_lock.current_processor_has_lock());
+		ASSERT(m_write_lock.is_locked_by_current_thread());
 		ASSERT(x < m_width && y < m_height);
 		auto& cell = m_buffer[y * m_width + x];
 		cell.codepoint = codepoint;
@@ -488,7 +488,7 @@ namespace Kernel
 
 	void VirtualTTY::putcodepoint(uint32_t codepoint)
 	{
-		ASSERT(m_write_lock.current_processor_has_lock());
+		ASSERT(m_write_lock.is_locked_by_current_thread());
 
 		switch (codepoint)
 		{
@@ -534,7 +534,7 @@ namespace Kernel
 
 	bool VirtualTTY::putchar_impl(uint8_t ch)
 	{
-		ASSERT(m_write_lock.current_processor_has_lock());
+		ASSERT(m_write_lock.is_locked_by_current_thread());
 
 		uint32_t codepoint = ch;