RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 07:58:11 +00:00
Code Issues Activity Actions

Kernel: Fix a few deadlocks with Thread::m_lock and g_scheduler_lock

Browse source 
g_scheduler_lock cannot safely be acquired after Thread::m_lock
because another processor may already hold g_scheduler_lock and wait
for the same Thread::m_lock.
This commit is contained in:
Tom 2020-10-25 20:22:59 -06:00 • committed by Andreas Kling
parent 8c764319ad
commit 1e2e3eed62
6 changed files with 55 additions and 37 deletions
Download patch file Download diff file Expand all files Collapse all files

27
Kernel/Syscalls/fork.cpp
View file

@ -79,24 +79,25 @@ pid_t Process::sys$fork(RegisterState& regs)
dbg() << "fork: child will begin executing at " << String::format("%w", child_tss.cs) << ":" << String::format("%x", child_tss.eip) << " with stack " << String::format("%w", child_tss.ss) << ":" << String::format("%x", child_tss.esp) << ", kstack " << String::format("%w", child_tss.ss0) << ":" << String::format("%x", child_tss.esp0);
#endif
ScopedSpinLock lock(m_lock);
for (auto& region : m_regions) {
#ifdef FORK_DEBUG
dbg() << "fork: cloning Region{" << &region << "} '" << region.name() << "' @ " << region.vaddr();
#endif
auto& child_region = child->add_region(region.clone());
child_region.map(child->page_directory());
if (&region == m_master_tls_region)
child->m_master_tls_region = child_region.make_weak_ptr();
}
{
ScopedSpinLock lock(g_processes_lock);
ScopedSpinLock lock(m_lock);
for (auto& region : m_regions) {
#ifdef FORK_DEBUG
dbg() << "fork: cloning Region{" << &region << "} '" << region.name() << "' @ " << region.vaddr();
#endif
auto& child_region = child->add_region(region.clone());
child_region.map(child->page_directory());
if (&region == m_master_tls_region)
child->m_master_tls_region = child_region.make_weak_ptr();
}
ScopedSpinLock processes_lock(g_processes_lock);
g_processes->prepend(child);
child->ref(); // This reference will be dropped by Process::reap
}
ScopedSpinLock lock(g_scheduler_lock);
child_first_thread->set_affinity(Thread::current()->affinity());
child_first_thread->set_state(Thread::State::Runnable);
return child->pid().value();