Re: [Qemu-devel] coroutine-ucontext broken for x86-32

[Kevin Wolf]

Am 08.05.2012 21:35, schrieb Jan Kiszka:
> Hi,
> 
> I hunted down a fairly subtle corruption of the VCPU thread signal mask
> in KVM mode when using the ucontext version of coroutines:
> 
> coroutine_new calls getcontext, makecontext, swapcontext. Those
> functions get/set also the signal mask of the caller. Unfortunately,
> they only use the sigprocmask syscall on i386, not the rt_sigprocmask
> version. So they do not properly save/restore the blocked RT signals,
> namely our SIG_IPI - it becomes unblocke this way.

If other coroutine backends work (sigaltstack?), we could try to detect
the situation in configure and set the right default. Not sure what the
condition is, glibc + i386?

Kevin