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Kernel: Fix Lock racing to the WaitQueue

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There was a time window between releasing Lock::m_lock and calling into
the lock's WaitQueue where someone else could take m_lock and bring two
threads into a deadlock situation.

Fix this issue by holding Lock::m_lock until interrupts are disabled by
either Thread::wait_on() or WaitQueue::wake_one().
This commit is contained in:
Andreas Kling 2020-01-12 18:46:41 +01:00
parent 61e6b1fb7c
commit 41376d4662
5 changed files with 13 additions and 10 deletions
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3
Kernel/Thread.h
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@ -1,5 +1,6 @@
#pragma once
#include <AK/Atomic.h>
#include <AK/Function.h>
#include <AK/IntrusiveList.h>
#include <AK/OwnPtr.h>
@ -300,7 +301,7 @@ public:
return block<ConditionBlocker>(state_string, move(condition));
}
void wait_on(WaitQueue& queue, Thread* beneficiary = nullptr, const char* reason = nullptr);
void wait_on(WaitQueue& queue, Atomic<bool>* lock = nullptr, Thread* beneficiary = nullptr, const char* reason = nullptr);
void wake_from_queue();
void unblock();