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052cb717f5
The PyThreadState field gains a reference count field to avoid issues with PyThreadState being a dangling pointer to freed memory. The refcount starts with a value of two: one reference is owned by the interpreter's linked list of thread states and one reference is owned by the OS thread. The reference count is decremented when the thread state is removed from the interpreter's linked list and before the OS thread calls `PyThread_hang_thread()`. The thread that decrements it to zero frees the `PyThreadState` memory. The `holds_gil` field is moved out of the `_status` bit field, to avoid a data race where on thread calls `PyThreadState_Clear()`, modifying the `_status` bit field while the OS thread reads `holds_gil` when attempting to acquire the GIL. The `PyThreadState.state` field now has `_Py_THREAD_SHUTTING_DOWN` as a possible value. This corresponds to the `_PyThreadState_MustExit()` check. This avoids race conditions in the free threading build when checking `_PyThreadState_MustExit()`.
76 lines
2.3 KiB
C
76 lines
2.3 KiB
C
#ifndef Py_INTERNAL_TSTATE_H
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#define Py_INTERNAL_TSTATE_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef Py_BUILD_CORE
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# error "this header requires Py_BUILD_CORE define"
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#endif
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#include "pycore_brc.h" // struct _brc_thread_state
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#include "pycore_freelist_state.h" // struct _Py_freelists
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#include "pycore_mimalloc.h" // struct _mimalloc_thread_state
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#include "pycore_qsbr.h" // struct qsbr
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// Every PyThreadState is actually allocated as a _PyThreadStateImpl. The
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// PyThreadState fields are exposed as part of the C API, although most fields
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// are intended to be private. The _PyThreadStateImpl fields not exposed.
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typedef struct _PyThreadStateImpl {
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// semi-public fields are in PyThreadState.
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PyThreadState base;
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// The reference count field is used to synchronize deallocation of the
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// thread state during runtime finalization.
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Py_ssize_t refcount;
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// These are addresses, but we need to convert to ints to avoid UB.
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uintptr_t c_stack_top;
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uintptr_t c_stack_soft_limit;
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uintptr_t c_stack_hard_limit;
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PyObject *asyncio_running_loop; // Strong reference
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PyObject *asyncio_running_task; // Strong reference
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/* Head of circular linked-list of all tasks which are instances of `asyncio.Task`
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or subclasses of it used in `asyncio.all_tasks`.
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*/
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struct llist_node asyncio_tasks_head;
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struct _qsbr_thread_state *qsbr; // only used by free-threaded build
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struct llist_node mem_free_queue; // delayed free queue
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#ifdef Py_GIL_DISABLED
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struct _gc_thread_state gc;
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struct _mimalloc_thread_state mimalloc;
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struct _Py_freelists freelists;
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struct _brc_thread_state brc;
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struct {
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// The per-thread refcounts
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Py_ssize_t *values;
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// Size of the refcounts array.
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Py_ssize_t size;
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// If set, don't use per-thread refcounts
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int is_finalized;
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} refcounts;
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// Index to use to retrieve thread-local bytecode for this thread
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int32_t tlbc_index;
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// When >1, code objects do not immortalize their non-string constants.
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int suppress_co_const_immortalization;
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#endif
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#if defined(Py_REF_DEBUG) && defined(Py_GIL_DISABLED)
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Py_ssize_t reftotal; // this thread's total refcount operations
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#endif
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} _PyThreadStateImpl;
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_INTERNAL_TSTATE_H */
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