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Re: [PATCH 0/2] nptl: Update struct pthread_unwind_buf
On Sun, Feb 25, 2018 at 4:58 AM, Florian Weimer <email@example.com> wrote:
> * H. J. Lu:
>> Let me rephrase. Can a function, which contains cancellation points,
>> return to its caller after cancellation happened?
> I don't think it can. It's undefined to use longjmp to jump out of a
> cancellation handler. On the C++ side, we make sure that the
> unwinding always proceeds, even across catch (...) blocks which
> swallow the exception.
libpthread cancellation implementation passes cancel_jmp_buf to
libgcc unwinder, which saves and restores shadow stack register
for C++ exception. How can libgcc unwinder tell when to save and
restore shadow stack register?