force_sig_info

Behavior of force_sig_info

• If SIGXXX is blocked or ignored: unblock SIGXXX, reset action to SIG_DFL

Force_sig_info in some special environment

• kvm_arch_vcpu_ioctl_run(), SIGXXX is blocked
  • SIGXXX is unblocked, but before returning from kernel:kvm_arch_vcpu_ioctl_run(), it is blocked again (restore host signal mask).
• In sys_rt_sigtimedwait(), SIGXXX is blocked
  • SIGXXX is unblocked, but before returning from sys_rt_sigtimedwait(), it is blocked again (restore to original signal mask).