Two defects found in review of the Linux delivery:
A raise right after scePthreadCreate reached the new thread before
RunThread set currentThread, so scePthreadSelf() in the handler adopted
a second handle, and could deadlock on glibc's thread lock when the
signal interrupted pthread_getattr_np. The creator now blocks all
signals around the std::thread construction, so the child starts with
them blocked, and RunThread restores the creator's mask once the thread
is registered, as libthr does. A raise in that window stays pending and
is delivered just before the entry runs.
A handler that set reserved MXCSR bits made rt_sigreturn fail with
SIGSEGV. The MXCSR the handler leaves is now masked with the frame's
MXCSR_MASK (0xffbf when it reads 0), as FreeBSD's fpusetregs does, on
both platforms; Windows also keeps CONTEXT.MxCsr equal to
FltSave.MxCsr.
guest_raise_exception raises right after each of 50 thread creations and
checks scePthreadSelf() in the handler, and its context round trip sets
a reserved MXCSR bit and FZ and checks that only FZ is kept.
AI-assisted: yes
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LwJx7AHrSUaMGSpEGhL1Kb
c356112f32