On 11/27/2016 11:02 AM, Ken Brown wrote:
> On 11/27/2016 9:03 AM, Girish Joglekar wrote:
>> Hi Ken,
>> Thank you for your reply on the Cygwin mailing list. I have created a
>> slightly smaller test example smaller than what I had created in Feb.
>> Attached is a tar file. After make insall if you run TEST.x and click
>> the Open button, it gives segmentation fault.
>> Hope you will be able to help.
>> Thank you.
>> Girish
>
> Please keep the discussion on the mailing list so that people who might
> be able to help will see it. I personally am not familiar with X11
> programming, so I'm not one of those people.
>
> I do have a few comments, however:
>
> 1. This may be slightly smaller than your previous program, but it is
> still *very* far from a small test case. You really can't expect people
> to debug a program of this size for you.
>
> 2. I suggest that you build with -Wall (as Marco already suggested in
> the earlier discussion) and fix all the compiler warnings. I saw
> several that need attention (aside from the many "unused variable"
> warnings). It wouldn't hurt to also use -Wextra.
>
> 3. I also suggest that you use gdb to find out where the program is
> crashing and why. You made a start on that in the discussion last
> March, but you didn't follow through. (By the way, I recommend building
> without optimization; otherwise you may not be able to get accurate
> information about the crash from gdb.)
>
> 4. If, after the steps above, you still think the crash is due to a
> Cygwin bug rather than a programming error, then try to extract from
> your program a test case as small as possible that reproduces the crash.
I've looked at this a little, and the crash occurs because of a bad value of a
pointer to a font list. I'm attaching an annotated transcript of a gdb session
that illustrates this. I didn't try to figure out where the bad pointer came
from.
As a workaround, you can avoid the crash by removing from mosprshx.c all uses
of spreadSheetFont, as in the following patch:
--- mosprshx.c~ 2016-11-27 08:46:12.000000000 -0500
+++ mosprshx.c 2016-11-29 14:58:23.114377500 -0500
@@ -29,8 +29,6 @@
0x00, 0x7c, 0x07, 0x1e, 0x0f, 0x07, 0x9e, 0x03, 0xfc, 0x01, 0xf8, 0x00,
0x70, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00};
-static char *spreadSheetFont =
"-adobe-courier-medium-r-normal--12-120-75-75-m-70-iso8859-1";
-
#ifdef __STDC__
static void mosprshCreateCheckMarkPixmap(Widget pushButton)
#else
@@ -208,11 +206,6 @@
if(isParentManaged)
XtUnmanageChild(parentFM);
- fromValue.addr = spreadSheetFont;
- fromValue.size = utStringLength(fromValue.addr) + 1;
- toValue.addr = NULL;
- XtConvertAndStore(parentFM,XmRString,&fromValue,XmRFontList,&toValue);
-
ac = 0;
XtSetArg(al[ac],XmNuserData,(XtPointer)spreadSheetSize); ac++;
spreadSheet = XmCreateForm(parentFM,"SpreadSheet",al,ac);
@@ -234,9 +227,6 @@
XtSetArg(al[ac],XmNtraversalOn,FALSE); ac++;
}
XtSetArg(al[ac],XmNcolumns,longestFixedColumnSize+1); ac++;
- if(toValue.addr) {
- XtSetArg(al[ac],XmNfontList,*(unsigned int *)toValue.addr); ac++;
- }
for(i1=0 ; i1<nRows ; i1++) {
sprintf(widgetName,"fixedColumnRow%d",i1);
fixedColumnTF[i1] = XmCreateTextField(fixedColumn,widgetName,al,ac);
@@ -264,9 +254,6 @@
if(cellSize > 0) {
XtSetArg(al[ac],XmNcolumns,cellSize); ac++;
}
- if(toValue.addr) {
- XtSetArg(al[ac],XmNfontList,*(unsigned int *)toValue.addr); ac++;
- }
for(j1=0 ; j1<nColumns ; j1++) {
sprintf(widgetName,"fixedRowColumn%d",j1);
fixedRowTF[j1] = XmCreateTextField(fixedRow,widgetName,al,ac);
@@ -294,9 +281,6 @@
XtSetArg(al[ac],XmNcolumns,cellSize); ac++;
XtSetArg(al[ac],XmNmaxLength,cellSize); ac++;
}
- if(toValue.addr) {
- XtSetArg(al[ac],XmNfontList,*(unsigned int *)toValue.addr); ac++;
- }
sprintf(widgetName,"column%drow%d",j1,i1);
variableRowAndColumnTF[loc] =
XmCreateTextField(variableColumnFM[j1],widgetName,al,ac); loc++;
}
@@ -886,15 +870,3 @@
*nColumns = 0;
}
}
-
-
-#ifdef __STDC__
-char *moGetSpreadsheetFont()
-#else
-char *moGetSpreadsheetFont()
-#endif
-{
- return(spreadSheetFont);
-}
-
-
Ken
Thread 1 "TEST.x" received signal SIGSEGV, Segmentation fault.
0x00000003fc68c4e5 in XmRenderTableCopy (table=0xaeeb0, tags=tags@entry=0x0,
tag_count=tag_count@entry=0)
at /usr/src/debug/motif-2.3.6-1/lib/Xm/XmRenderT.c:1709
1709 if (_XmRTDisplay(table))
[Crash here because the value of table is bogus. See below.
+bt
#0 0x00000003fc68c4e5 in XmRenderTableCopy (table=0xaeeb0,
tags=tags@entry=0x0, tag_count=tag_count@entry=0)
at /usr/src/debug/motif-2.3.6-1/lib/Xm/XmRenderT.c:1709
#1 0x00000003fc6831ba in XmFontListCopy (fontlist=<optimized out>)
at /usr/src/debug/motif-2.3.6-1/lib/Xm/XmFontList.c:637
#2 0x00000003fc657920 in InitializeTextStruct (tf=tf@entry=0x6000af730)
at /usr/src/debug/motif-2.3.6-1/lib/Xm/TextF.c:7295
#3 0x00000003fc657e67 in Initialize (request=request@entry=0x6000afb40,
new_w=new_w@entry=0x6000af730, args=args@entry=0xffffbd60,
num_args=num_args@entry=0xffffb320)
at /usr/src/debug/motif-2.3.6-1/lib/Xm/TextF.c:7817
#4 0x00000003fc469bb1 in CallInitialize (
class=0x3fc72c440 <xmTextFieldClassRec>,
req_widget=req_widget@entry=0x6000afb40,
new_widget=new_widget@entry=0x6000af730, args=args@entry=0xffffbd60,
num_args=num_args@entry=8) at /usr/src/debug/libXt-1.1.5-1/src/Create.c:226
#5 0x00000003fc46a65c in xtCreate (
name=name@entry=0xffffb950 "fixedColumnRow0", class=class@entry=0x0,
widget_class=widget_class@entry=0x3fc72c440 <xmTextFieldClassRec>,
parent=0x1fc5dd590, parent@entry=0x6000af0d0, default_screen=0x600052780,
args=args@entry=0xffffbd60, num_args=num_args@entry=8,
typed_args=typed_args@entry=0x0, num_typed_args=num_typed_args@entry=0,
parent_constraint_class=0x3fc720dc0 <xmFormClassRec>,
post_proc=post_proc@entry=0x3fc469bf0 <widgetPostProc>)
at /usr/src/debug/libXt-1.1.5-1/src/Create.c:416
#6 0x00000003fc46a906 in _XtCreateWidget (
name=name@entry=0xffffb950 "fixedColumnRow0",
widget_class=widget_class@entry=0x3fc72c440 <xmTextFieldClassRec>,
parent=parent@entry=0x6000af0d0, args=args@entry=0xffffbd60,
num_args=num_args@entry=8, typed_args=typed_args@entry=0x0,
num_typed_args=num_typed_args@entry=0)
at /usr/src/debug/libXt-1.1.5-1/src/Create.c:570
#7 0x00000003fc46abd9 in XtCreateWidget (name=0xffffb950 "fixedColumnRow0",
widget_class=0x3fc72c440 <xmTextFieldClassRec>, parent=0x6000af0d0,
args=0xffffbd60, num_args=8)
at /usr/src/debug/libXt-1.1.5-1/src/Create.c:589
#8 0x00000003fc658a81 in XmCreateTextField (parent=<optimized out>,
name=<optimized out>, arglist=<optimized out>, argcount=<optimized out>)
at /usr/src/debug/motif-2.3.6-1/lib/Xm/TextF.c:10645
#9 0x000000010040882d in mosprshCreateSpreadsheet (parentFM=0x6000acc60,
spreadSheetTitle=0x100421087 "Measuring Unit Specification",
rowNames=0x6000ab4f0, columnNames=0x6000ab4b0, cellSize=0,
mosprshCheckButtonCallback=0x0) at mosprshx.c:242
[...]
+p *table
$1 = (struct __XmRenderTableRec *) 0x56f700001ea1
+p *$
Cannot access memory at address 0x56f700001ea1
+f 2
#2 0x00000003fc657920 in InitializeTextStruct (tf=tf@entry=0x6000af730)
at /usr/src/debug/motif-2.3.6-1/lib/Xm/TextF.c:7295
7295 TextF_FontList(tf) =
(XmFontList)XmFontListCopy(TextF_FontList(tf));
+p tf->text.font_list
$2 = (XmFontList) 0xaeeb0
[This is the bad pointer that was propagated to XmRenderTableCopy. I
didn't chase down where it came from.]
--
Problem reports: http://cygwin.com/problems.html
FAQ: http://cygwin.com/faq/
Documentation: http://cygwin.com/docs.html
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
