mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-11-03 03:22:27 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

gh-118727: Don't drop the GIL in drop_gil() unless the current thread holds it (#118745)

Browse source 
`drop_gil()` assumes that its caller is attached, which means that the current
thread holds the GIL if and only if the GIL is enabled, and the enabled-state
of the GIL won't change. This isn't true, though, because `detach_thread()`
calls `_PyEval_ReleaseLock()` after detaching and
`_PyThreadState_DeleteCurrent()` calls it after removing the current thread
from consideration for stop-the-world requests (effectively detaching it).

Fix this by remembering whether or not a thread acquired the GIL when it last
attached, in `PyThreadState._status.holds_gil`, and check this in `drop_gil()`
instead of `gil->enabled`.

This fixes a crash in `test_multiprocessing_pool_circular_import()`, so I've
reenabled it.
This commit is contained in:
Brett Simmers 2024-05-23 16:59:35 -04:00 • committed by GitHub
parent b30d30c747
commit be1dfccdf2
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
5 changed files with 73 additions and 60 deletions
Download patch file Download diff file Expand all files Collapse all files

4
Include/cpython/pystate.h
View file

@ -83,6 +83,8 @@ struct _ts {
unsigned int bound_gilstate:1;
/* Currently in use (maybe holds the GIL). */
unsigned int active:1;
/* Currently holds the GIL. */
unsigned int holds_gil:1;
/* various stages of finalization */
unsigned int finalizing:1;
@ -90,7 +92,7 @@ struct _ts {
unsigned int finalized:1;
/* padding to align to 4 bytes */
unsigned int :24;
unsigned int :23;
} _status;
#ifdef Py_BUILD_CORE
# define _PyThreadState_WHENCE_NOTSET -1

7
Include/internal/pycore_ceval.h
View file

@ -131,11 +131,10 @@ extern int _PyEval_ThreadsInitialized(void);
extern void _PyEval_InitGIL(PyThreadState *tstate, int own_gil);
extern void _PyEval_FiniGIL(PyInterpreterState *interp);
// Acquire the GIL and return 1. In free-threaded builds, this function may
// return 0 to indicate that the GIL was disabled and therefore not acquired.
extern int _PyEval_AcquireLock(PyThreadState *tstate);
extern void _PyEval_AcquireLock(PyThreadState *tstate);
extern void _PyEval_ReleaseLock(PyInterpreterState *, PyThreadState *);
extern void _PyEval_ReleaseLock(PyInterpreterState *, PyThreadState *,
int final_release);
#ifdef Py_GIL_DISABLED
// Returns 0 or 1 if the GIL for the given thread's interpreter is disabled or