Re: signal SIGSEGV, Segmentation fault

[Andreas Höschler]

Hi Richard,

Aha, interesting. But this still rings no bell (no idea how this could be).

Well, anything that overwrite the memory location in which 'self' is stored could cause this.
The most common thing (as suggested by Wolfgang) would be if the object was deallocated and the memory re-used (a retain/release error),

The object is not deallocated as I have shown with a log message in -dealloc. 

but buffer overruns could also corrupt the memory.
Fred's suggestion of running under valgrind should help find the problem in either case.

This gave me nothing (see below).

valgrind reports

2018-05-22 11:23:16.323 TimberNav[7685:7685] MapView drawRect {x = 0; y = 0; width = 817; height = 334} ... _osmDrawing 0

2018-05-22 11:23:16.327 TimberNav[7685:7685] After super drawRect:rect

2018-05-22 11:23:16.328 TimberNav[7685:7685] bums

==7685== Use of uninitialised value of size 4

==7685==    at 0x8064DC2: _i_MapView__drawRect_ (MapView.m:168)

==7685==    by 0xBEAD8617: ???

==7685==

==7685== Invalid write of size 1

==7685==    at 0x8064DC2: _i_MapView__drawRect_ (MapView.m:168)

==7685==    by 0xBEAD8617: ???

==7685==  Address 0x134 is not stack'd, malloc'd or (recently) free'd

==7685==

==7685==

==7685== Process terminating with default action of signal 11 (SIGSEGV)

==7685==  Access not within mapped region at address 0x134

==7685==    at 0x8064DC2: _i_MapView__drawRect_ (MapView.m:168)

==7685==    by 0xBEAD8617: ???

==7685==  If you believe this happened as a result of a stack

==7685==  overflow in your program's main thread (unlikely but

==7685==  possible), you can try to increase the size of the

==7685==  main thread stack using the --main-stacksize= flag.

==7685==  The main thread stack size used in this run was 8388608.

==7685==

==7685== HEAP SUMMARY:

==7685==     in use at exit: 7,671,140 bytes in 99,510 blocks

==7685==   total heap usage: 345,414 allocs, 245,904 frees, 38,473,207 bytes allocated

==7685==

==7685== LEAK SUMMARY:

==7685==    definitely lost: 49,171 bytes in 1,041 blocks

==7685==    indirectly lost: 457,010 bytes in 8,088 blocks

==7685==      possibly lost: 3,449,433 bytes in 46,039 blocks

==7685==    still reachable: 3,715,526 bytes in 44,342 blocks

==7685==                       of which reachable via heuristic:

==7685==                         newarray           : 69,036 bytes in 303 blocks

==7685==         suppressed: 0 bytes in 0 blocks

==7685== Rerun with --leak-check=full to see details of leaked memory

==7685==

==7685== For counts of detected and suppressed errors, rerun with: -v

==7685== Use --track-origins=yes to see where uninitialised values come from

==7685== ERROR SUMMARY: 4 errors from 3 contexts (suppressed: 0 from 0)

==7685== Use of uninitialised value of size 4

==7685==    at 0x8064DC2: _i_MapView__drawRect_ (MapView.m:168)

==7685==    by 0xBEAD8617: ???

==7685==

==7685== Invalid write of size 1

==7685==    at 0x8064DC2: _i_MapView__drawRect_ (MapView.m:168)

==7685==    by 0xBEAD8617: ???

==7685==  Address 0x134 is not stack'd, malloc'd or (recently) free'd

==7685==

==7685==

==7685== Process terminating with default action of signal 11 (SIGSEGV)

==7685==  Access not within mapped region at address 0x134

==7685==    at 0x8064DC2: _i_MapView__drawRect_ (MapView.m:168)

==7685==    by 0xBEAD8617: ???

==7685==  If you believe this happened as a result of a stack

==7685==  overflow in your program's main thread (unlikely but

==7685==  possible), you can try to increase the size of the

==7685==  main thread stack using the --main-stacksize= flag.

==7685==  The main thread stack size used in this run was 8388608.

==7685==

==7685== HEAP SUMMARY:

==7685==     in use at exit: 7,671,140 bytes in 99,510 blocks

==7685==   total heap usage: 345,414 allocs, 245,904 frees, 38,473,207 bytes allocated

==7685==

==7685== LEAK SUMMARY:

==7685==    definitely lost: 49,171 bytes in 1,041 blocks

==7685==    indirectly lost: 457,010 bytes in 8,088 blocks

==7685==      possibly lost: 3,449,433 bytes in 46,039 blocks

==7685==    still reachable: 3,715,526 bytes in 44,342 blocks

==7685==                       of which reachable via heuristic:

==7685==                         newarray           : 69,036 bytes in 303 blocks

==7685==         suppressed: 0 bytes in 0 blocks

==7685== Rerun with --leak-check=full to see details of leaked memory

==7685==

==7685== For counts of detected and suppressed errors, rerun with: -v

==7685== Use --track-origins=yes to see where uninitialised values come from

==7685== ERROR SUMMARY: 4 errors from 3 contexts (suppressed: 0 from 0)

- (void)drawRect:(NSRect)rect

{

   NSLog(@"MapView drawRect %@ ... _osmDrawing %d", NSStringFromRect(rect), _osmDrawing);

   [super drawRect:rect];

   NSLog(@"After super drawRect:rect");

   [self bums];

   //   if (image != nil && _osmDrawing == NO)

     {

      NSImage *image = [self image];

      NSSize imageSize = [image size];

      

      _routeVisible = YES;    // <--- this is line 168

      // draw route

      NSLog(@"routeVisible: %d", _routeVisible);

      NSLog(@"routePath: %@", _routePath);

      ...

}

Thanks,

 Andreas