Segmentation fault for EXTRASAMPLES

1) Ubuntu 16.04.1 LTS
2) libtiff5-dev
3) Reading a tiff (RGB, 32 bits per pixel), the tiff has "extra samples" tag. The next code should return number of extra samples:

uint16 m;
TIFFGetField(tif, TIFFTAG_EXTRASAMPLES, &m);

4) The above code gives "Segmentation fault" when reading this tag exactly, other tags can be read.
An old 3.x version didn't have this issue, verified with the same file.