Hi,
Wine-4.4 throws Unhandled Page fault on write access errors on NetBSD i386 -current. I did some debugging and found that it was due to _lwp_makecontext(3) segfaulting as it tried to access memory that was out-of-bounds. However, the real reason was pthread_attr_setstack(3) setting up a guard of 65536 bytes which Wine didn't account for. I am aware that the manpage of pthread_attr_setstack(3) is dated and it states that no default guard will be allocated. I will indeed send a patch to amend that. In order to work around the issue, I have tried setting the guard to 0 explicitly using pthread_attr_setguardsize(3). As far as I know this change shouldn't affect any other platforms. Additionally, it also solves the initial problem I had, which was wine giving me black windows instead of the UI; an inadvertent side-effect of the same issue.
OK?