* [PATCH 1/2] gdb: move gdbpy_gil into python-internal.h
@ 2023-12-07 11:02 Alexandra Hájková
2023-12-07 11:02 ` [PATCH 2/2] gdb/python: avoid use of _PyOS_ReadlineTState Alexandra Hájková
2023-12-08 18:04 ` [PATCH 1/2] gdb: move gdbpy_gil into python-internal.h Tom Tromey
0 siblings, 2 replies; 4+ messages in thread
From: Alexandra Hájková @ 2023-12-07 11:02 UTC (permalink / raw)
To: gdb-patches
Move gdbpy_gil class into python-internal.h, the next
commit wants to make use of this class from a file other
than python.c.
---
gdb/python/python-internal.h | 24 ++++++++++++++++++++++++
gdb/python/python.c | 24 ------------------------
2 files changed, 24 insertions(+), 24 deletions(-)
diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 86eb5436f2a..14e15574685 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -772,6 +772,30 @@ class gdbpy_allow_threads
PyThreadState *m_save;
};
+/* A helper class to save and restore the GIL, but without touching
+ the other globals that are handled by gdbpy_enter. */
+
+class gdbpy_gil
+{
+public:
+
+ gdbpy_gil ()
+ : m_state (PyGILState_Ensure ())
+ {
+ }
+
+ ~gdbpy_gil ()
+ {
+ PyGILState_Release (m_state);
+ }
+
+ DISABLE_COPY_AND_ASSIGN (gdbpy_gil);
+
+private:
+
+ PyGILState_STATE m_state;
+};
+
/* Use this after a TRY_EXCEPT to throw the appropriate Python
exception. */
#define GDB_PY_HANDLE_EXCEPTION(Exception) \
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 8a36673a3e4..f9df57b9fd5 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -264,30 +264,6 @@ gdbpy_enter::finalize ()
python_gdbarch = current_inferior ()->arch ();
}
-/* A helper class to save and restore the GIL, but without touching
- the other globals that are handled by gdbpy_enter. */
-
-class gdbpy_gil
-{
-public:
-
- gdbpy_gil ()
- : m_state (PyGILState_Ensure ())
- {
- }
-
- ~gdbpy_gil ()
- {
- PyGILState_Release (m_state);
- }
-
- DISABLE_COPY_AND_ASSIGN (gdbpy_gil);
-
-private:
-
- PyGILState_STATE m_state;
-};
-
/* Set the quit flag. */
static void
--
2.41.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 2/2] gdb/python: avoid use of _PyOS_ReadlineTState
2023-12-07 11:02 [PATCH 1/2] gdb: move gdbpy_gil into python-internal.h Alexandra Hájková
@ 2023-12-07 11:02 ` Alexandra Hájková
2023-12-08 18:04 ` Tom Tromey
2023-12-08 18:04 ` [PATCH 1/2] gdb: move gdbpy_gil into python-internal.h Tom Tromey
1 sibling, 1 reply; 4+ messages in thread
From: Alexandra Hájková @ 2023-12-07 11:02 UTC (permalink / raw)
To: gdb-patches
From: Andrew Burgess <aburgess@redhat.com>
In python/py-gdb-readline.c we make use of _PyOS_ReadlineTState,
however, this variable is no longer public in Python 3.13, and so GDB
no longer builds.
We are making use of _PyOS_ReadlineTState in order to re-acquire the
Python Global Interpreter Lock (GIL). The _PyOS_ReadlineTState
variable is set in Python's outer readline code prior to calling the
user (GDB) supplied readline callback function, which for us is
gdbpy_readline_wrapper. The gdbpy_readline_wrapper function is called
without the GIL held.
Instead of using _PyOS_ReadlineTState, I propose that we switch to
calling PyGILState_Ensure() and PyGILState_Release(). These functions
will acquire the GIL based on the current thread. I think this should
be sufficient; I can't imagine why we'd be running
gdbpy_readline_wrapper on one thread on behalf of a different Python
thread.... that would be unexpected I think.
---
gdb/python/py-gdb-readline.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/gdb/python/py-gdb-readline.c b/gdb/python/py-gdb-readline.c
index 124cec8055d..699d396dd19 100644
--- a/gdb/python/py-gdb-readline.c
+++ b/gdb/python/py-gdb-readline.c
@@ -56,13 +56,11 @@ gdbpy_readline_wrapper (FILE *sys_stdin, FILE *sys_stdout,
if (except.reason == RETURN_QUIT)
return NULL;
- /* The thread state is nulled during gdbpy_readline_wrapper,
- with the original value saved in the following undocumented
- variable (see Python's Parser/myreadline.c and
- Modules/readline.c). */
- PyEval_RestoreThread (_PyOS_ReadlineTState);
+
+ /* This readline callback is called without the GIL held. */
+ gdbpy_gil gil;
+
gdbpy_convert_exception (except);
- PyEval_SaveThread ();
return NULL;
}
--
2.41.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] gdb: move gdbpy_gil into python-internal.h
2023-12-07 11:02 [PATCH 1/2] gdb: move gdbpy_gil into python-internal.h Alexandra Hájková
2023-12-07 11:02 ` [PATCH 2/2] gdb/python: avoid use of _PyOS_ReadlineTState Alexandra Hájková
@ 2023-12-08 18:04 ` Tom Tromey
1 sibling, 0 replies; 4+ messages in thread
From: Tom Tromey @ 2023-12-08 18:04 UTC (permalink / raw)
To: Alexandra Hájková; +Cc: gdb-patches
>>>>> "Alexandra" == Alexandra Hájková <ahajkova@redhat.com> writes:
Alexandra> Move gdbpy_gil class into python-internal.h, the next
Alexandra> commit wants to make use of this class from a file other
Alexandra> than python.c.
Thank you.
Approved-By: Tom Tromey <tom@tromey.com>
Tom
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 2/2] gdb/python: avoid use of _PyOS_ReadlineTState
2023-12-07 11:02 ` [PATCH 2/2] gdb/python: avoid use of _PyOS_ReadlineTState Alexandra Hájková
@ 2023-12-08 18:04 ` Tom Tromey
0 siblings, 0 replies; 4+ messages in thread
From: Tom Tromey @ 2023-12-08 18:04 UTC (permalink / raw)
To: Alexandra Hájková; +Cc: gdb-patches
>>>>> "Alexandra" == Alexandra Hájková <ahajkova@redhat.com> writes:
Alexandra> Instead of using _PyOS_ReadlineTState, I propose that we switch to
Alexandra> calling PyGILState_Ensure() and PyGILState_Release(). These functions
Alexandra> will acquire the GIL based on the current thread. I think this should
Alexandra> be sufficient; I can't imagine why we'd be running
Alexandra> gdbpy_readline_wrapper on one thread on behalf of a different Python
Alexandra> thread.... that would be unexpected I think.
Makes sense to me.
Approved-By: Tom Tromey <tom@tromey.com>
Tom
^ permalink raw reply [flat|nested] 4+ messages in thread
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