Created attachment 137008 [details]
Backtrace for all threads

SUMMARY
When I made the smudge_and_color brush be 1000px in size and tried to make a stroke, I encountered a crash.

STEPS TO REPRODUCE
1. Choose the brush.
2. Change the size to 1000px
3. Try to make a stroke

OBSERVED RESULT
Crash

EXPECTED RESULT
No crash

SOFTWARE/OS VERSIONS
Krita

 Version: 5.0.0-prealpha (git 1ea07f2)
 Languages: pl, pl_PL, pl
 Hidpi: true

Qt

  Version (compiled): 5.12.9
  Version (loaded): 5.12.9

ADDITIONAL INFORMATION
(Backtrace from the appimage, so not much info)
Thread 606 "Thread (pooled)" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fff52f90700 (LWP 37588)]
0x00007fffbdd95ae6 in void KisMyPaintSurface::getColorImpl<unsigned short>(MyPaintSurface*, float, float, float, float*, float*, float*, float*) () from /tmp/.mount_krita-KxIZVN/usr/lib/kritaplugins/kritamypaintop.so
(gdb) bt
#0  0x00007fffbdd95ae6 in void KisMyPaintSurface::getColorImpl<unsigned short>(MyPaintSurface*, float, float, float, float*, float*, float*, float*) () from /tmp/.mount_krita-KxIZVN/usr/lib/kritaplugins/kritamypaintop.so
#1  0x00007fffbdb4fa7c in update_smudge_color () from /tmp/.mount_krita-KxIZVN/usr/lib/kritaplugins/../libmypaint.so
#2  0x00007fffbdb5068d in prepare_and_draw_dab () from /tmp/.mount_krita-KxIZVN/usr/lib/kritaplugins/../libmypaint.so
#3  0x00007fffbdb51488 in mypaint_brush_stroke_to_internal () from /tmp/.mount_krita-KxIZVN/usr/lib/kritaplugins/../libmypaint.so
#4  0x00007fffbdb51931 in mypaint_brush_stroke_to () from /tmp/.mount_krita-KxIZVN/usr/lib/kritaplugins/../libmypaint.so
#5  0x00007fffbdd8565a in KisMyPaintPaintOp::paintAt(KisPaintInformation const&) () from /tmp/.mount_krita-KxIZVN/usr/lib/kritaplugins/kritamypaintop.so
#6  0x00007ffff57dc994 in ?? () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libkritaimage.so.17
#7  0x00007ffff57dbcce in ?? () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libkritaimage.so.17
#8  0x00007ffff57dc1e4 in KisPaintOp::paintBezierCurve(KisPaintInformation const&, QPointF const&, QPointF const&, KisPaintInformation const&, KisDistanceInformation*) () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libkritaimage.so.17
#9  0x00007ffff6da4bf7 in KisMaskedFreehandStrokePainter::paintBezierCurve(KisPaintInformation const&, QPointF const&, QPointF const&, KisPaintInformation const&) () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libkritaui.so.17
#10 0x00007ffff6d9e8e5 in FreehandStrokeStrategy::doStrokeCallback(KisStrokeJobData*) () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libkritaui.so.17
#11 0x00007ffff578cfb4 in ?? () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libkritaimage.so.17
#12 0x00007ffff3c4af77 in ?? () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libQt5Core.so.5
#13 0x00007ffff3c46b2e in ?? () from /tmp/.mount_krita-KxIZVN/usr/bin/../lib/libQt5Core.so.5
#14 0x00007fffee219609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#15 0x00007ffff38bd293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95