[Tcl-bugs] [ tktoolkit-Bugs-1609465 ] Zero Page error in tkTextDisp.c

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Bugs item #1609465, was opened at 2006-12-05 18:12
Message generated for change (Comment added) made by dkf
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Category: 18. [text]
Group: current: 8.4.14
Status: Open
Resolution: None
Priority: 9
Private: No
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Jeffrey Hobbs (hobbs)
Summary: Zero Page error in tkTextDisp.c

Initial Comment:
Hi,
I have a crash in my TCL/Tk application because of a corrupted pointer in tkTextDisp.c.  We get this crash on UNIX, when we use a text widget to show our log file.
The exact location of the corrupted pointer is line 2279 in tkTextDisp.c
 
Below is source code snippet:
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    /*
     * First recompute what's supposed to be displayed.
     */
    
    UpdateDisplayInfo(textPtr);
    dInfoPtr->dLinesInvalidated = 0;
    
    /*
     * See if it's possible to bring some parts of the screen up-to-date
     * by scrolling (copying from other parts of the screen).
     */
    
    for (dlPtr = dInfoPtr->dLinePtr; dlPtr != NULL; dlPtr = dlPtr->nextPtr) {   ----------------------> dlPtr is corrupted after many many iterations
        register DLine *dlPtr2;
        int offset, height, y, oldY;
        TkRegion damageRgn;
    
        if ((dlPtr->oldY == -1) || (dlPtr->y == dlPtr->oldY)
                || ((dlPtr->oldY + dlPtr->height) > dInfoPtr->maxY)) {
            continue;
        }
    
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
     
We are filtering (i.e., hiding, raising) a lot of messages in our text widget using 'elide' option and 'tag raise' command.
Has anybody seen this kind of problem before ?
The version of Tk we are using is 8.4.14
 
Thanks,
 
Kishore Kollu
kis...@me... 
Mentor Graphics

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>Comment By: Donal K. Fellows (dkf)
Date: 2006-12-12 10:24

Message:
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user_id=79902
Originator: NO

Fault must lie elsewhere; nowhere in that loop are any (relevant) pointers
manipulated. Somewhere (probably in elide processing) must be setting the
dlPtr->nextPtr to a bogus zero-page address *that isn't NULL*. I don't know
the code well enough to hunt this.

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Comment By: kolluk (kolluk)
Date: 2006-12-11 18:19

Message:
Logged In: YES 
user_id=1662655
Originator: NO

Hi,
Can anybody please update on the status on this issue ?
Thanks
Kishore
kis...@me... 
Mentor Graphics 

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You can respond by visiting: 
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