|
|
@@ -0,0 +1,227 @@
|
|
|
+From c47bae859a5af0d95224d90000df0e529f7c5aa0 Mon Sep 17 00:00:00 2001
|
|
|
+From: Kevin Buettner <kevinb@redhat.com>
|
|
|
+Date: Wed, 27 May 2020 20:05:40 -0700
|
|
|
+Subject: [PATCH] Fix Python3.9 related runtime problems
|
|
|
+
|
|
|
+Python3.9b1 is now available on Rawhide. GDB w/ Python 3.9 support
|
|
|
+can be built using the configure switch -with-python=/usr/bin/python3.9.
|
|
|
+
|
|
|
+Attempting to run gdb/Python3.9 segfaults on startup:
|
|
|
+
|
|
|
+ #0 0x00007ffff7b0582c in PyEval_ReleaseLock () from /lib64/libpython3.9.so.1.0
|
|
|
+ #1 0x000000000069ccbf in do_start_initialization ()
|
|
|
+ at worktree-test1/gdb/python/python.c:1789
|
|
|
+ #2 _initialize_python ()
|
|
|
+ at worktree-test1/gdb/python/python.c:1877
|
|
|
+ #3 0x00000000007afb0a in initialize_all_files () at init.c:237
|
|
|
+ ...
|
|
|
+
|
|
|
+Consulting the the documentation...
|
|
|
+
|
|
|
+https://docs.python.org/3/c-api/init.html
|
|
|
+
|
|
|
+...we find that PyEval_ReleaseLock() has been deprecated since version
|
|
|
+3.2. It recommends using PyEval_SaveThread or PyEval_ReleaseThread()
|
|
|
+instead. In do_start_initialization, in gdb/python/python.c, we
|
|
|
+can replace the calls to PyThreadState_Swap() and PyEval_ReleaseLock()
|
|
|
+with a single call to PyEval_SaveThread. (Thanks to Keith Seitz
|
|
|
+for working this out.)
|
|
|
+
|
|
|
+With that in place, GDB gets a little bit further. It still dies
|
|
|
+on startup, but the backtrace is different:
|
|
|
+
|
|
|
+ #0 0x00007ffff7b04306 in PyOS_InterruptOccurred ()
|
|
|
+ from /lib64/libpython3.9.so.1.0
|
|
|
+ #1 0x0000000000576e86 in check_quit_flag ()
|
|
|
+ at worktree-test1/gdb/extension.c:776
|
|
|
+ #2 0x0000000000576f8a in set_active_ext_lang (now_active=now_active@entry=0x983c00 <extension_language_python>)
|
|
|
+ at worktree-test1/gdb/extension.c:705
|
|
|
+ #3 0x000000000069d399 in gdbpy_enter::gdbpy_enter (this=0x7fffffffd2d0,
|
|
|
+ gdbarch=0x0, language=0x0)
|
|
|
+ at worktree-test1/gdb/python/python.c:211
|
|
|
+ #4 0x0000000000686e00 in python_new_inferior (inf=0xddeb10)
|
|
|
+ at worktree-test1/gdb/python/py-inferior.c:251
|
|
|
+ #5 0x00000000005d9fb9 in std::function<void (inferior*)>::operator()(inferior*) const (__args#0=<optimized out>, this=0xccad20)
|
|
|
+ at /usr/include/c++/10/bits/std_function.h:617
|
|
|
+ #6 gdb::observers::observable<inferior*>::notify (args#0=0xddeb10,
|
|
|
+ this=<optimized out>)
|
|
|
+ at worktree-test1/gdb/../gdbsupport/observable.h:106
|
|
|
+ #7 add_inferior_silent (pid=0)
|
|
|
+ at worktree-test1/gdb/inferior.c:113
|
|
|
+ #8 0x00000000005dbcb8 in initialize_inferiors ()
|
|
|
+ at worktree-test1/gdb/inferior.c:947
|
|
|
+ ...
|
|
|
+
|
|
|
+We checked with some Python Developers and were told that we should
|
|
|
+acquire the GIL prior to calling any Python C API function. We
|
|
|
+definitely don't have the GIL for calls of PyOS_InterruptOccurred().
|
|
|
+
|
|
|
+I moved class_gdbpy_gil earlier in the file and use it in
|
|
|
+gdbpy_check_quit_flag() to acquire (and automatically release) the
|
|
|
+GIL.
|
|
|
+
|
|
|
+With those changes in place, I was able to run to a GDB prompt. But,
|
|
|
+when trying to quit, it segfaulted again due to due to some other
|
|
|
+problems with gdbpy_check_quit_flag():
|
|
|
+
|
|
|
+ Thread 1 "gdb" received signal SIGSEGV, Segmentation fault.
|
|
|
+ 0x00007ffff7bbab0c in new_threadstate () from /lib64/libpython3.9.so.1.0
|
|
|
+ (top-gdb) bt 8
|
|
|
+ #0 0x00007ffff7bbab0c in new_threadstate () from /lib64/libpython3.9.so.1.0
|
|
|
+ #1 0x00007ffff7afa5ea in PyGILState_Ensure.cold ()
|
|
|
+ from /lib64/libpython3.9.so.1.0
|
|
|
+ #2 0x000000000069b58c in gdbpy_gil::gdbpy_gil (this=<synthetic pointer>)
|
|
|
+ at worktree-test1/gdb/python/python.c:278
|
|
|
+ #3 gdbpy_check_quit_flag (extlang=<optimized out>)
|
|
|
+ at worktree-test1/gdb/python/python.c:278
|
|
|
+ #4 0x0000000000576e96 in check_quit_flag ()
|
|
|
+ at worktree-test1/gdb/extension.c:776
|
|
|
+ #5 0x000000000057700c in restore_active_ext_lang (previous=0xe9c050)
|
|
|
+ at worktree-test1/gdb/extension.c:729
|
|
|
+ #6 0x000000000088913a in do_my_cleanups (
|
|
|
+ pmy_chain=0xc31870 <final_cleanup_chain>,
|
|
|
+ old_chain=0xae5720 <sentinel_cleanup>)
|
|
|
+ at worktree-test1/gdbsupport/cleanups.cc:131
|
|
|
+ #7 do_final_cleanups ()
|
|
|
+ at worktree-test1/gdbsupport/cleanups.cc:143
|
|
|
+
|
|
|
+In this case, we're trying to call a Python C API function after
|
|
|
+Py_Finalize() has been called from finalize_python(). I made
|
|
|
+finalize_python set gdb_python_initialized to false and then cause
|
|
|
+check_quit_flag() to return early when it's false.
|
|
|
+
|
|
|
+With these changes in place, GDB seems to be working again with
|
|
|
+Python3.9b1. I think it likely that there are other problems lurking.
|
|
|
+I wouldn't be surprised to find that there are other calls into Python
|
|
|
+where we don't first make sure that we have the GIL. Further changes
|
|
|
+may well be needed.
|
|
|
+
|
|
|
+I see no regressions testing on Rawhide using a GDB built with the
|
|
|
+default Python version (3.8.3) versus one built using Python 3.9b1.
|
|
|
+
|
|
|
+I've also tested on Fedora 28, 29, 30, 31, and 32 (all x86_64) using
|
|
|
+the default (though updated) system installed versions of Python on
|
|
|
+those OSes. This means that I've tested against Python versions
|
|
|
+2.7.15, 2.7.17, 2.7.18, 3.7.7, 3.8.2, and 3.8.3. In each case GDB
|
|
|
+still builds without problem and shows no regressions after applying
|
|
|
+this patch.
|
|
|
+
|
|
|
+gdb/ChangeLog:
|
|
|
+
|
|
|
+2020-MM-DD Kevin Buettner <kevinb@redhat.com>
|
|
|
+ Keith Seitz <keiths@redhat.com>
|
|
|
+
|
|
|
+ * python/python.c (do_start_initialization): For Python 3.9 and
|
|
|
+ later, call PyEval_SaveThread instead of PyEval_ReleaseLock.
|
|
|
+ (class gdbpy_gil): Move to earlier in file.
|
|
|
+ (finalize_python): Set gdb_python_initialized.
|
|
|
+ (gdbpy_check_quit_flag): Acquire GIL via gdbpy_gil. Return early
|
|
|
+ when not initialized.
|
|
|
+
|
|
|
+
|
|
|
+[import into Buildroot, removing ChangeLog change to avoid conflict]
|
|
|
+Signed-off-by: Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
|
|
|
+
|
|
|
+---
|
|
|
+ gdb/ChangeLog | 10 ++++++++
|
|
|
+ gdb/python/python.c | 56 ++++++++++++++++++++++++---------------------
|
|
|
+ 2 files changed, 40 insertions(+), 26 deletions(-)
|
|
|
+
|
|
|
+diff --git a/gdb/python/python.c b/gdb/python/python.c
|
|
|
+index 67f362b852d..4bdd2201abc 100644
|
|
|
+--- a/gdb/python/python.c
|
|
|
++++ b/gdb/python/python.c
|
|
|
+@@ -238,6 +238,30 @@ gdbpy_enter::~gdbpy_enter ()
|
|
|
+ PyGILState_Release (m_state);
|
|
|
+ }
|
|
|
+
|
|
|
++/* 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
|
|
|
+@@ -251,6 +275,10 @@ gdbpy_set_quit_flag (const struct extension_language_defn *extlang)
|
|
|
+ static int
|
|
|
+ gdbpy_check_quit_flag (const struct extension_language_defn *extlang)
|
|
|
+ {
|
|
|
++ if (!gdb_python_initialized)
|
|
|
++ return 0;
|
|
|
++
|
|
|
++ gdbpy_gil gil;
|
|
|
+ return PyOS_InterruptOccurred ();
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -943,30 +971,6 @@ gdbpy_source_script (const struct extension_language_defn *extlang,
|
|
|
+
|
|
|
+ /* Posting and handling events. */
|
|
|
+
|
|
|
+-/* 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;
|
|
|
+-};
|
|
|
+-
|
|
|
+ /* A single event. */
|
|
|
+ struct gdbpy_event
|
|
|
+ {
|
|
|
+@@ -1616,6 +1620,7 @@ finalize_python (void *ignore)
|
|
|
+
|
|
|
+ Py_Finalize ();
|
|
|
+
|
|
|
++ gdb_python_initialized = false;
|
|
|
+ restore_active_ext_lang (previous_active);
|
|
|
+ }
|
|
|
+
|
|
|
+@@ -1785,8 +1790,7 @@ do_start_initialization ()
|
|
|
+ return false;
|
|
|
+
|
|
|
+ /* Release the GIL while gdb runs. */
|
|
|
+- PyThreadState_Swap (NULL);
|
|
|
+- PyEval_ReleaseLock ();
|
|
|
++ PyEval_SaveThread ();
|
|
|
+
|
|
|
+ make_final_cleanup (finalize_python, NULL);
|
|
|
+
|
|
|
+--
|
|
|
+2.26.3
|
|
|
+
|
Thomas De Schampheleire