Inside the manylinux2010 i686 docker, log(-1) returns nan, but it is a different nan than the one expected by the data used in test_umath_accuracy. The tests expect 0xffc00000, but the glibc log() function on this platform returns 0x7fc00000. Both are nan, but assert_array_max_ulp uses nulp_diff which is very literal:

>>> import numpy as np, numpy.testing
>>> x = np.int32(0xffc00000).view(np.float32)
>>> y = np.int32(0x7fc00000).view(np.float32)
>>> print(x, y)
nan nan
>>> numpy.testing._private.utils.nulp_diff(y, x)
8388608.0

np.isnan returns True for both.

I think the test be relaxed to accept more than one nan.