Re: [PATCH 03/10] x86/cet: Signal handling for shadow stack

[Dave Hansen]

On 06/07/2018 01:12 PM, Yu-cheng Yu wrote:
>>> +int cet_restore_signal(unsigned long ssp)
>>> +{
>>> +       if (!current->thread.cet.shstk_enabled)
>>> +               return 0;
>>> +       return cet_set_shstk_ptr(ssp);
>>> +}
>> This will blow up if the shadow stack enabled state changes in a
>> signal handler.  Maybe we don't care.
> Yes, the task will get a control protection fault.

Sounds like something to add to the very long list of things that are
unwise to do in a signal handler.  Great manpage fodder.