Attachment 109170 Details for Bug 86075 – Crash description and test program

Crash description and test program

crash_bug_report_x (text/plain), 3.60 KB, created by Ian Gay on 2014-11-09 19:38:30 UTC

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Creator: Ian Gay

Created: 2014-11-09 19:38:30 UTC

Size: 3.60 KB

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>Xserver crashes when drawing multi-segment dashed lines that
>extend outside visible window. Running Linux, Opensuse 13.1
>with kernel 3.17. Running on i5-2500K using on-board graphics.
>X server is version 7.6_1.16.1, Intel driver is version
>2.99.916
>The crash occurs both on KDE and icewm.
>
>After a crash, log file shows the following
>---------------- begin log segment --------------
>[  3111.676] (EE) 14: /usr/bin/Xorg (0x400000+0x2cba1) [0x42cba1]
>[  3111.676] (EE) 
>[  3111.676] (EE) Segmentation fault at address 0x7fffdf4a1004
>[  3111.676] (EE) 
>Fatal server error:
>[  3111.676] (EE) Caught signal 11 (Segmentation fault). Server aborting
>[  3111.676] (EE) 
>[  3111.676] (EE) 
>Please consult the The X.Org Foundation support 
>	 at http://wiki.x.org
> for help. 
>----------------- end log segment ----------------
>
>The crash can be reproduced by the short program listed below.
>It does not crash on every draw call, hence the program loop.
>Usually it crashes in < 100 iterations of the loop.
>
>The conditions for crashing are fairly specific; if you make
>_any_ of the following changes to the test program, it will no
>longer crash:
>a) Increase the window size to 600x600
>b) Change the line width to 2 or more
>c) For equal on-off dashes, set the dash length to something
>   which is not 3, 8, 9, 10, 15, 17 or 19 (These are the only
>   dash lengths <= 20 which cause the crash).
>d) Change the join to JoinMiter   
>   
>---------------------- Test program -----------------
>/* compile with  
>gcc -O2 -Wall -o x5 x5.c -L /usr/X11R6/lib -lX11 -lm
>*/
> #include <X11/Xlib.h>
> #include <X11/Xutil.h>
> #include <stdio.h>
> #include <stdlib.h>
>
>   XPoint pts[] = {
>   {229, 229}, {223, 234}, {217, 240}, {211, 246}, {205, 252}, {200, 258}, {195, 264}, {189, 270}, 
>   {184, 276}, {179, 282}, {174, 288}, {169, 294}, {164, 300}, {160, 306}, {155, 312}, {151, 318}, 
>   {146, 324}, {142, 330}, {138, 336}, {134, 341}, {130, 347}, {126, 353}, {123, 358}, {119, 364}, 
>   {116, 370}, {113, 375}, {109, 381}, {106, 386}, {104, 391}, {101, 397}, { 98, 402}, { 96, 407}, 
>   { 93, 412}, { 91, 417}, { 89, 422}, { 87, 427}, { 86, 432}, { 84, 436}, { 82, 441}, { 81, 445}, 
>   { 80, 450}, { 79, 454}, { 78, 458}, { 77, 462}, { 77, 466}, { 76, 470}, { 76, 474}, { 76, 478}, 
>   { 76, 481}, { 76, 485}, { 77, 488}, { 77, 491}, { 78, 494}, { 79, 497}, { 80, 500}, { 81, 502}, 
>   { 82, 505}, { 84, 507}, { 86, 509}, { 88, 512}
>   };
>
>   Display *d;
>   int s;
>   GC gc;
> 
>int main() {
>   int i;
>   Window w;
>   XEvent e;
>   unsigned int width = 1;
>   char dash[] = {3,3};
>   int join = JoinBevel;
>   int CYCLES = 50000;
>   
>   d=XOpenDisplay(NULL);
>   if(d==NULL) {
>     printf("Cannot open display\n");
>     exit(1);
>   }
>   s=DefaultScreen(d);
>   gc = XDefaultGC(d, s);
>   
>   XSetLineAttributes(d, gc, width, LineOnOffDash, CapButt, join);
>
>   w=XCreateSimpleWindow(d, RootWindow(d, s), 100, 100, 400, 400, 1,
>                         BlackPixel(d, s), WhitePixel(d, s));
>
>   XSelectInput(d, w, ExposureMask | KeyPressMask);
> 
>   XMapWindow(d, w);
>
>   while(1) {
>     XNextEvent(d, &e);
>     if(e.type==Expose) {
>         printf("Running\n");
>         XSetDashes(d, gc, 0, dash, sizeof(dash));
>         
>         for (i=0; i<CYCLES;  i++){
>            XClearWindow(d, w);
>            XSetForeground(d, gc, 0x0000ff);
>            XDrawLines(d, w, gc, pts, sizeof(pts)/sizeof(XPoint), CoordModeOrigin);
>            XFlush(d);
>         }
>         printf("Done %d cycles\n", CYCLES);
>      }
>                        /* exit on key press */
>     if(e.type==KeyPress) {
>         break;
>     }
>   } 
>   XDestroyWindow(d, w);
>   XCloseDisplay(d);
>   return 0;
>}
>-------------- End of test program -----------------

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