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LibCore: Atomically ref-count SharedSingleProducerCircularQueue guts

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This fixes two race conditions and ASAN crashes in the test for the
same.

The first comes from destroying the internals struct, which was
previously using the standard, thread-unsafe RefCounted CRTP. The
second is from destroying the name, which is secretly another
RefCounted object, in a thread-unsafe manner.
This commit is contained in:
Andrew Kaster 2025-05-24 04:29:58 -06:00 • committed by Andrew Kaster
commit 228211205a
Notes: github-actions[bot] 2025-05-24 12:53:21 +00:00
1 changed files with 9 additions and 9 deletions
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18
Libraries/LibCore/SharedCircularQueue.h
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@ -7,6 +7,7 @@
#pragma once #pragma once
#include <AK/AtomicRefCounted.h>
#include <AK/BuiltinWrappers.h> #include <AK/BuiltinWrappers.h>
#include <AK/ByteString.h> #include <AK/ByteString.h>
#include <AK/Debug.h> #include <AK/Debug.h>
@ -162,22 +163,24 @@ private:
}; };
class RefCountedSharedMemorySPCQ class RefCountedSharedMemorySPCQ
: public RefCounted<RefCountedSharedMemorySPCQ> : public AtomicRefCounted<RefCountedSharedMemorySPCQ>
, public AnonymousBuffer { , public AnonymousBuffer {
friend class SharedSingleProducerCircularQueue; friend class SharedSingleProducerCircularQueue;
public: public:
SharedMemorySPCQ* m_queue; SharedMemorySPCQ* m_queue;
ByteString m_name;
~RefCountedSharedMemorySPCQ() ~RefCountedSharedMemorySPCQ()
{ {
dbgln_if(SHARED_QUEUE_DEBUG, "destructed SSPCQ at {:p}, shared mem: {:p}", this, m_queue); dbgln_if(SHARED_QUEUE_DEBUG, "destructed SSPCQ at {:p} named {}, shared mem: {:p}", this, m_name, m_queue);
} }
private: private:
RefCountedSharedMemorySPCQ(AnonymousBuffer anon_buf, SharedMemorySPCQ* shared_queue) RefCountedSharedMemorySPCQ(AnonymousBuffer anon_buf, SharedMemorySPCQ* shared_queue, ByteString name)
: AnonymousBuffer(anon_buf) : AnonymousBuffer(anon_buf)
, m_queue(shared_queue) , m_queue(shared_queue)
, m_name(move(name))
{ {
} }
}; };
@ -188,19 +191,16 @@ private:
return Error::from_string_literal("Unexpected error when creating shared queue from raw memory"); return Error::from_string_literal("Unexpected error when creating shared queue from raw memory");
auto name = ByteString::formatted("SharedSingleProducerCircularQueue@{:x}", anon_buf.fd()); auto name = ByteString::formatted("SharedSingleProducerCircularQueue@{:x}", anon_buf.fd());
dbgln_if(SHARED_QUEUE_DEBUG, "successfully mmapped {} at {:p}", name, shared_queue); dbgln_if(SHARED_QUEUE_DEBUG, "successfully mmapped {} at {:p}", name, shared_queue);
auto ref_counted = new (nothrow) RefCountedSharedMemorySPCQ(anon_buf, shared_queue); auto ref_counted = new (nothrow) RefCountedSharedMemorySPCQ(anon_buf, shared_queue, move(name));
return SharedSingleProducerCircularQueue<T, Size> { move(name), adopt_ref(*ref_counted) }; return SharedSingleProducerCircularQueue<T, Size> { adopt_ref(*ref_counted) };
} }
SharedSingleProducerCircularQueue(ByteString name, RefPtr<RefCountedSharedMemorySPCQ> queue) SharedSingleProducerCircularQueue(RefPtr<RefCountedSharedMemorySPCQ> queue)
: m_queue(queue) : m_queue(queue)
, m_name(move(name))
{ {
} }
RefPtr<RefCountedSharedMemorySPCQ> m_queue; RefPtr<RefCountedSharedMemorySPCQ> m_queue;
ByteString m_name {};
}; };
} }