When does pthread_create() return EINVAL?

[Manuel Lauss]

Hello,

When does pthread_create() return EINVAL?
I use qemu-user for mipsel, and after updating a python package in the mipsel
userland, pthread_create() in qemu-user started returning EINVAL.  I
looked through the source of pthread_create, but could not find an
explicit EINVAL anywhere.

(glibc.git x86_64)

Thanks!
    Manuel