RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 05:38:11 +00:00
Code Issues Activity Actions

Kernel: Stop swallowing thread unblocks while process is stopped

Browse source 
This easily led to kernel deadlocks if the stopped thread held an
important global mutex (like the disk cache lock) while blocking.
Resolve this by ensuring stopped threads have a chance to return to the
userland boundary before actually stopping.
This commit is contained in:
Idan Horowitz 2024-02-09 21:13:41 +02:00 • committed by Andreas Kling
parent 458e990b7b
commit e38ccebfc8
4 changed files with 24 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

14
Kernel/Tasks/Thread.cpp
View file

@ -314,8 +314,8 @@ void Thread::unblock_from_blocker(Blocker& blocker)
SpinlockLocker block_lock(m_block_lock);
if (m_blocker != &blocker)
return;
if (!should_be_stopped() && !is_stopped())
unblock();
VERIFY(!is_stopped());
unblock();
};
if (Processor::current_in_irq() != 0) {
Processor::deferred_call_queue([do_unblock = move(do_unblock), self = try_make_weak_ptr().release_value_but_fixme_should_propagate_errors()]() {
@ -1273,14 +1273,8 @@ void Thread::set_state(State new_state, u8 stop_signal)
m_stop_state = previous_state != Thread::State::Running ? previous_state : Thread::State::Runnable;
auto& process = this->process();
if (!process.set_stopped(true)) {
process.for_each_thread([&](auto& thread) {
if (&thread == this)
return;
if (thread.is_stopped())
return;
dbgln_if(THREAD_DEBUG, "Stopping peer thread {}", thread);
thread.set_state(Thread::State::Stopped, stop_signal);
});
// Note that we don't explicitly stop peer threads, we let them stop on their own the next time they
// enter/exit a syscall, or once their current time slice runs out.
process.unblock_waiters(Thread::WaitBlocker::UnblockFlags::Stopped, stop_signal);
// Tell the parent process (if any) about this change.
if (auto parent = Process::from_pid_ignoring_jails(process.ppid())) {