TK State Change Issue Causing Seg Fault

[jweezy24]

Hello,

On my Linux machine I kept encountering this error.

Caught signal 11 (Segmentation fault: Sent by the kernel at address (nil))
==== backtrace (tid:   3042) ====
 0 0x000000000004d212 ucs_event_set_fd_get()  ???:0
 1 0x000000000004d3dd ucs_event_set_fd_get()  ???:0
 2 0x000000000003cae0 __sigaction()  ???:0
 3 0x00000000000ac860 DisplayText.lto_priv.0()  :0
 4 0x000000000011f64e TclServiceIdle()  /usr/src/debug/tcl/tcl8.6.14/generic/tclTimer.c:751
 5 0x00000000000fbe96 Tcl_DoOneEvent()  /usr/src/debug/tcl/tcl8.6.14/generic/tclNotify.c:980
 6 0x000000000001e064 Tk_UpdateObjCmd()  :0
 7 0x000000000002f800 TclNRRunCallbacks()  /usr/src/debug/tcl/tcl8.6.14/generic/tclBasic.c:4539
 8 0x00000000000096a3 ???()  /usr/lib/python3.12/lib-dynload/_tkinter.cpython-312-x86_64-linux-gnu.so:0
 9 0x0000000000186918 _PyObject_GetMethod()  ???:0
10 0x00000000001a4b6d PyObject_Vectorcall()  ???:0
11 0x000000000018931f _PyEval_EvalFrameDefault()  ???:0
12 0x00000000001e166c PyObject_CallFinalizerFromDealloc()  ???:0
13 0x000000000018e71b _PyEval_EvalFrameDefault()  ???:0
14 0x00000000001e166c PyObject_CallFinalizerFromDealloc()  ???:0
15 0x0000000000009aac ???()  /usr/lib/python3.12/lib-dynload/_tkinter.cpython-312-x86_64-linux-gnu.so:0
16 0x000000000002f800 TclNRRunCallbacks()  /usr/src/debug/tcl/tcl8.6.14/generic/tclBasic.c:4539
17 0x00000000000317e5 TclEvalEx()  /usr/src/debug/tcl/tcl8.6.14/generic/tclBasic.c:5408
18 0x0000000000032097 Tcl_EvalEx()  /usr/src/debug/tcl/tcl8.6.14/generic/tclBasic.c:5073
19 0x0000000000016cd0 Tk_BindEvent()  /usr/src/debug/tk/tk8.6.14/unix/../generic/tkBind.c:2593
20 0x000000000001ccb3 TkBindEventProc()  ???:0
21 0x000000000002eec7 Tk_HandleEvent()  ???:0
22 0x000000000002f17d WindowEventProc()  :0
23 0x00000000000fbc68 Tcl_ServiceEvent()  /usr/src/debug/tcl/tcl8.6.14/generic/tclNotify.c:670
24 0x00000000000fbec0 Tcl_DoOneEvent()  /usr/src/debug/tcl/tcl8.6.14/generic/tclNotify.c:903
25 0x0000000000004807 ???()  /usr/lib/python3.12/lib-dynload/_tkinter.cpython-312-x86_64-linux-gnu.so:0
26 0x000000000025848a PyUnicode_RPartition()  ???:0
27 0x00000000001a4b6d PyObject_Vectorcall()  ???:0
28 0x000000000018931f _PyEval_EvalFrameDefault()  ???:0
29 0x00000000001e1c65 PyObject_CallFinalizer()  ???:0
30 0x00000000001e1708 PyObject_CallFinalizerFromDealloc()  ???:0
31 0x000000000018e71b _PyEval_EvalFrameDefault()  ???:0
32 0x000000000024d0f5 PyEval_EvalCode()  ???:0
33 0x00000000002703ea PySet_Pop()  ???:0
34 0x000000000026b2ef _PyObject_GC_Resize()  ???:0
35 0x0000000000285924 PyImport_GetMagicNumber()  ???:0
36 0x0000000000284c51 _PyRun_SimpleFileObject()  ???:0
37 0x000000000028480f _PyRun_AnyFileObject()  ???:0
38 0x000000000027d034 Py_RunMain()  ???:0
39 0x000000000023860c Py_BytesMain()  ???:0
40 0x0000000000025c88 __libc_init_first()  ???:0
41 0x0000000000025d4c __libc_start_main()  ???:0
42 0x0000000000001045 _start()  ???:0
=================================

I am on python 3.12. Everything else works perfectly fine.

After some debugging, I found that the error was from these lines.

self.log_textbox.insert(tk.END, txt, tags)
self.log_textbox.yview_moveto(1)
self.log_textbox.configure(state=tk.DISABLED)

It turns out that the TK state was switching too quickly so it caused a segfault within the self.log function. I remedied the problem by changing the log function to the code below.

    def disable_log_textbox(self):
        try:
            if self.log_textbox.winfo_exists():
                self.log_textbox.configure(state=tk.DISABLED)
        except Exception as e:
            print(f"Error disabling log_textbox: {e}")
    
    def log(self, txt: str = '', tags: list = [], where: str = 'both', link: str = '') -> None:
        """ Log to main window (where can be 'screen', 'file', or 'both') """
        if where != 'file':
            
            try:
                # Ensure this is done on the main thread
                if not self.log_textbox.winfo_exists():
                    return  # Exit if widget does not exist
                
                self.log_textbox.configure(state=tk.NORMAL)

                if link:
                    tags = tags + self.hyperlink.add(partial(self.openLink, link))
                
                
                self.log_textbox.insert(tk.END, txt, tags)
                self.log_textbox.yview_moveto(1)  # Scroll to last line
                self.log_textbox.after(0, self.disable_log_textbox)
            except Exception as e:
                print(f"Error updating log_textbox: {e}")

        if where != 'screen' and self.log_file and not self.log_file.closed:
            
            try:
                if tags == 'error':
                    txt = f'ERROR: {txt}'
                self.log_file.write(txt)
                self.log_file.flush()
            except Exception as e:
                print(f"Error writing to log file: {e}")

The disable_log_textbox function ensures that the state changes do not conflict. Since adding this code I have had no issues with the program. I am not familiar with TK so I do not know if this is the best solution. Also, I do not know if this is only a problem on Linux as no other issues seem to be similar.

[gernophil]

@BabyFnord, don't you also get the segmenation 11 error on your Mac? IIRC we get this, after we sign the x86_64 package, maybe that's our solution?

[BabyFnord]

Yes @gernophil, exactly Segmentation fault: 11, albeit with noScribe Editor. Tho I dunno whether @jweezy24 refers to the Editor or its counterpart here. This is what I get:

standard	10:08:49.790788 +0200	Python	Current system appearance, (HLTB: 1), (SLS: 0)
standard	10:08:49.792104 +0200	Python	Post-registration system appearance: (HLTB: 1)
standard	10:08:49.851590 +0200	launchservicesd	CHECKIN:0x0-0x9c09c 1501 org.python.python
standard	10:08:49.854245 +0200	distnoted	register name: com.apple.sharedfilelist.change object: com.apple.LSSharedFileList.ApplicationRecentDocuments/org.python.python token: f4326 pid: 320
standard	10:08:49.861356 +0200	loginwindow	-[PersistentAppsSupport applicationReady:] | App: Python, ready, updating active tracking timer
standard	10:08:49.861452 +0200	loginwindow	-[ApplicationManager checkInAppContext:refCon:eventData:] |      checked in app : Python
standard	10:08:49.882717 +0200	distnoted	register name: com.apple.xctest.FakeForceTouchDevice object: org.python.python token: f4289 pid: 1501
standard	10:08:50.089709 +0200	Python	NSApp cache appearance:
-NSRequiresAquaSystemAppearance: 0
-appearance: (null)
-effectiveAppearance: <NSCompositeAppearance: 0x7fb424b02a20
 (
    "<NSAquaAppearance: 0x7fb424b01bb0>",
    "<NSSystemAppearance: 0x7fb424b02210>"
)>
standard	10:08:50.133332 +0200	distnoted	register name: com.apple.nsquiet_safe_quit_give_reason object: org.python.python token: f42cf pid: 1501
standard	10:08:50.307988 +0200	loginwindow	-[PersistentAppsSupport applicationQuit:] | for app:Python, _appTrackingState = 2
standard	10:08:50.308044 +0200	loginwindow	-[PersistentAppsSupport applicationQuit:] | App: Python, quit, updating active tracking timer
standard	10:08:53.615035 +0200	ReportCrash	Saved crash report for Python[1501] version 3.10.14 (3.10.14) to Python_2024-06-21-100853_BigMac.crash

See Python_2024-06-21-100853_BigMac.txt for a detailed crash log, if that helps. Would be terrific to solve Segmentation fault: 11!

[kaixxx]

possible solution: #75

[BabyFnord]

Thanks @jweezy24, looking forward to a commit @kaixxx @gernophil 😃