RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 09:38:11 +00:00
Code Issues Activity Actions

Kernel: Unwind kernel stacks before dying

Browse source 
While executing in the kernel, a thread can acquire various resources
that need cleanup, such as locks and references to RefCounted objects.
This cleanup normally happens on the exit path, such as in destructors
for various RAII guards. But we weren't calling those exit paths when
killing threads that have been executing in the kernel, such as threads
blocked on reading or sleeping, thus causing leaks.

This commit changes how killing threads works. Now, instead of killing
a thread directly, one is supposed to call thread->set_should_die(),
which will unblock it and make it unwind the stack if it is blocked
in the kernel. Then, just before returning to the userspace, the thread
will automatically die.
This commit is contained in:
Sergey Bugaev 2019-11-14 18:46:01 +03:00 • committed by Andreas Kling
parent 00e56cda0c
commit 1e1ddce9d8
4 changed files with 58 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

16
Kernel/Process.cpp
View file

@ -836,6 +836,7 @@ void Process::sys$exit(int status)
m_termination_status = status;
m_termination_signal = 0;
die();
current->die_if_needed();
ASSERT_NOT_REACHED();
}
@ -921,6 +922,7 @@ void Process::crash(int signal, u32 eip)
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(!is_dead());
ASSERT(&current->process() == this);
if (m_elf_loader && ksyms_ready)
dbgprintf("\033[31;1m%p %s\033[0m\n", eip, m_elf_loader->symbolicate(eip).characters());
@ -930,6 +932,9 @@ void Process::crash(int signal, u32 eip)
dump_regions();
ASSERT(is_ring3());
die();
// We can not return from here, as there is nowhere
// to unwind to, so die right away.
current->die_if_needed();
ASSERT_NOT_REACHED();
}
@ -2320,16 +2325,13 @@ void Process::die()
m_tracer->set_dead();
{
// Tell the threads to unwind and die.
InterruptDisabler disabler;
for_each_thread([](Thread& thread) {
if (thread.state() != Thread::State::Dead)
thread.set_state(Thread::State::Dying);
thread.set_should_die();
return IterationDecision::Continue;
});
}
if (!Scheduler::is_active())
Scheduler::pick_next_and_switch_now();
}
size_t Process::amount_virtual() const
@ -2831,9 +2833,9 @@ void Process::sys$exit_thread(void* code)
sys$exit(0);
return;
}
current->set_state(Thread::State::Dying);
current->set_should_die();
big_lock().unlock_if_locked();
Scheduler::pick_next_and_switch_now();
current->die_if_needed();
ASSERT_NOT_REACHED();
}