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Kernel: Disable SMP message handling while blocking a thread

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There were some race conditions on a thread getting unblocked before
being moved to the block queue
This commit is contained in:
Bananymous
2026-07-11 05:30:57 +03:00
parent 46e2d665e9
commit edc95e1c09
3 changed files with 24 additions and 11 deletions
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11
kernel/include/kernel/Processor.h
View File

@@ -104,10 +104,17 @@ namespace Kernel
static void pause()
{
__builtin_ia32_pause();
if (is_smp_enabled())
if (is_smp_enabled() && !smp_messages_disabled())
handle_smp_messages();
}
static bool smp_messages_disabled() { return read_gs_sized<bool>(offsetof(Processor, m_smp_messages_disabled)); }
static void set_disable_smp_messages(bool disabled)
{
ASSERT(smp_messages_disabled() != disabled);
write_gs_sized<bool>(offsetof(Processor, m_smp_messages_disabled), disabled);
}
vaddr_t stack_top_vaddr() const { return m_stack_vaddr + s_stack_size; }
paddr_t stack_top_paddr() const { return m_stack_paddr + s_stack_size; }
@@ -198,6 +205,8 @@ namespace Kernel
ProcessorID m_id { 0 };
uint8_t m_index { 0 };
bool m_smp_messages_disabled { false };
vaddr_t m_thread_syscall_stack;
Thread* m_sse_thread { nullptr };

2
kernel/kernel/Processor.cpp
View File

@@ -447,6 +447,8 @@ namespace Kernel
auto processor_id = current_id();
auto& processor = s_processors[processor_id.m_id];
ASSERT(!processor.m_smp_messages_disabled);
auto* pending = processor.m_smp_pending.exchange(nullptr);
if (pending == nullptr)
return set_interrupt_state(state);

22
kernel/kernel/Scheduler.cpp
View File

@@ -235,8 +235,12 @@ namespace Kernel
add_current_to_most_loaded(m_current->blocked ? &m_block_queue : &m_run_queue);
if (!m_current->blocked)
m_run_queue.add_thread_to_back(m_current);
else if (m_block_queue.add_thread_with_wake_time(m_current))
update_wake_up_deadline();
else
{
if (m_block_queue.add_thread_with_wake_time(m_current))
update_wake_up_deadline();
Processor::set_disable_smp_messages(false);
}
break;
case Thread::State::NotStarted:
ASSERT(!m_current->blocked);
@@ -383,13 +387,12 @@ namespace Kernel
{
if (!node->blocked)
return;
if (node != m_current)
m_block_queue.remove_node(node);
ASSERT(node != m_current);
m_block_queue.remove_node(node);
if (auto* blocker = node->blocker.load())
blocker->remove_thread_from_block_queue(node);
node->blocked = false;
if (node != m_current)
m_run_queue.add_thread_to_back(node);
m_run_queue.add_thread_to_back(node);
update_most_loaded_node_queue(node, &m_run_queue);
}
else
@@ -602,7 +605,6 @@ namespace Kernel
}
thread_info.node->processor_id = least_loaded_id;
Processor::send_smp_message(least_loaded_id, {
.type = Processor::SMPMessage::Type::NewThread,
.new_thread = thread_info.node
@@ -676,14 +678,14 @@ namespace Kernel
ASSERT(m_current->processor_id == Processor::current_id());
ASSERT(!m_current->blocked);
Processor::set_disable_smp_messages(true);
m_current->blocked = true;
m_current->wake_time_ns = wake_time_ns;
if (blocker)
if (blocker != nullptr)
blocker->add_thread_to_block_queue(m_current);
update_most_loaded_node_queue(m_current, &m_block_queue);
uint32_t lock_depth = 0;
if (mutex != nullptr)
{