Assertion failed: (pthreadret == 0), function _xcb_in_wake_up_next_reader, file xcb_in.c, line 926.

Dear XCB developers,

following the upgrade to libxcb 1.14, we have now a crash in one of our tools (http://flair.web.cern.ch/flair/)
with the crash report at the bottom of this email.
The problem appears at this line called in frame 11:
XPutImage(self->display, self->pixmap, self->gc, self->ximage, 0, 0, 0, 0, width, height);

Comparing with the libxcb 1.13, I managed to track down the issue to the variable “total_read” defined in xcbint.h.
Indeed, with the attached patch the crash disappears.

Do you have any suggestions how to fix the problem?

For sake of completeness, libxcb is installed via MacPorts.
If needed, I can provide additional details.

Thanks a lot for your help

——————————————————————
Luigi Salvatore ESPOSITO - CERN-EN/STI
Esplanade des Particules
CH-1211 Geneva 23
O +41 22 76 63419
——————————————————————


Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib         0x00007fff6da8733a __pthread_kill + 10
1   libsystem_pthread.dylib        0x00007fff6db43e60 pthread_kill + 430
2   libsystem_c.dylib              0x00007fff6da0e808 abort + 120
3   libsystem_c.dylib              0x00007fff6da0dac6 __assert_rtn + 314
4   libxcb.1.dylib                 0x00000001147c7746 _xcb_in_wake_up_next_reader + 89
5   libxcb.1.dylib                 0x00000001147c6dd6 _xcb_out_send + 125
6   libxcb.1.dylib                 0x00000001147c6d3e xcb_writev + 68
7   libX11.6.dylib                 0x00000001157fe8f9 _XSend + 315
8   libX11.6.dylib                 0x00000001157f42c7 PutSubImage + 1924
9   libX11.6.dylib                 0x00000001157f3c8b PutSubImage + 328
10  libX11.6.dylib                 0x00000001157f385f XPutImage + 424
11  geoviewer.so                   0x0000000115689233 Viewer_expose(ViewerObject*, _object*) + 163
12  org.python.python              0x000000010df3eb26 cfunction_call_varargs + 319
13  org.python.python              0x000000010dfd6b72 _PyEval_EvalFrameDefault + 9050
14  org.python.python              0x000000010dfddeb9 _PyEval_EvalCodeWithName + 2107
15  org.python.python              0x000000010df3ef21 _PyFunction_Vectorcall + 217
16  org.python.python              0x000000010df40f56 method_vectorcall + 372
17  org.python.python              0x000000010df3e80d PyVectorcall_Call + 108
18  _tkinter.cpython-38-darwin.so  0x000000010e8c0012 PythonCmd + 205
19  libtcl8.6.dylib                0x000000010e8ddaee TclNRRunCallbacks + 79
20  libtcl8.6.dylib                0x000000010e8ded06 TclEvalEx + 1987
21  libtcl8.6.dylib                0x000000010e8de53d Tcl_EvalEx + 26
22  libtk8.6.dylib                 0x000000010ebff362 Tk_BindEvent + 5754
23  libtk8.6.dylib                 0x000000010ec04fe9 TkBindEventProc + 334
24  libtk8.6.dylib                 0x000000010ec0c523 Tk_HandleEvent + 997
25  libtk8.6.dylib                 0x000000010ec0cc0c WindowEventProc + 96
26  libtcl8.6.dylib                0x000000010e985e78 Tcl_ServiceEvent + 136
27  libtcl8.6.dylib                0x000000010e98606d Tcl_DoOneEvent + 153
28  _tkinter.cpython-38-darwin.so  0x000000010e8be324 _tkinter_tkapp_mainloop + 342
29  org.python.python              0x000000010df45d4e method_vectorcall_FASTCALL + 250
30  org.python.python              0x000000010dfdd2f5 call_function + 346
31  org.python.python              0x000000010dfd66cd _PyEval_EvalFrameDefault + 7861
32  org.python.python              0x000000010dfddeb9 _PyEval_EvalCodeWithName + 2107
33  org.python.python              0x000000010df3ef21 _PyFunction_Vectorcall + 217
34  org.python.python              0x000000010df40e69 method_vectorcall + 135
35  org.python.python              0x000000010dfdd2f5 call_function + 346
36  org.python.python              0x000000010dfd66f0 _PyEval_EvalFrameDefault + 7896
37  org.python.python              0x000000010dfddeb9 _PyEval_EvalCodeWithName + 2107
38  org.python.python              0x000000010dfd4790 PyEval_EvalCode + 42
39  org.python.python              0x000000010e00c57d run_eval_code_obj + 102
40  org.python.python              0x000000010e00b9cb run_mod + 82
41  org.python.python              0x000000010e00a8a5 PyRun_FileExFlags + 160
42  org.python.python              0x000000010e009f89 PyRun_SimpleFileExFlags + 271
43  org.python.python              0x000000010e021834 Py_RunMain + 1836
44  org.python.python              0x000000010e021b90 pymain_main + 370
45  org.python.python              0x000000010e021be5 Py_BytesMain + 42
46  libdyld.dylib                  0x00007fff6d93fcc9 start + 1

_______________________________________________
Xcb mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/xcb

diff -ruN src.orig/xcb_conn.c src/xcb_conn.c
--- src.orig/xcb_conn.c	2020-02-22 21:50:14.000000000 +0100
+++ src/xcb_conn.c	2020-03-21 22:15:41.000000000 +0100
@@ -538,7 +538,7 @@
         return 0;
 
     pthread_mutex_lock(&c->iolock);
-    n = c->in.total_read;
+    //    n = c->in.total_read;
     pthread_mutex_unlock(&c->iolock);
     return n;
 }
diff -ruN src.orig/xcb_in.c src/xcb_in.c
--- src.orig/xcb_in.c	2020-02-22 21:50:14.000000000 +0100
+++ src/xcb_in.c	2020-03-21 22:14:18.000000000 +0100
@@ -1025,7 +1025,7 @@
             }
         }
 #endif
-        c->in.total_read += n;
+	//        c->in.total_read += n;
         c->in.queue_len += n;
     }
     while(read_packet(c))
diff -ruN src.orig/xcbint.h src/xcbint.h
--- src.orig/xcbint.h	2020-02-22 21:50:14.000000000 +0100
+++ src/xcbint.h	2020-03-21 22:13:10.000000000 +0100
@@ -136,7 +136,7 @@
     uint64_t request_expected;
     uint64_t request_read;
     uint64_t request_completed;
-    uint64_t total_read;
+  //    uint64_t total_read;
     struct reply_list *current_reply;
     struct reply_list **current_reply_tail;