Re: Request for implementation of KERN_PROC_SIGTRAMP sysctl

[Jason Thorpe <thorpej%me.com@localhost>]

> On Oct 29, 2021, at 7:54 AM, Jason Thorpe <thorpej%me.com@localhost> wrote:
> 
> 
> 
>> On Oct 29, 2021, at 2:45 AM, Martin Husemann <martin%duskware.de@localhost> wrote:
>> 
>> On Thu, Oct 28, 2021 at 11:14:39AM -0700, Jason Thorpe wrote:
>>> We really just need to kill the sigcontext stuff completely.  More to the point, we should version sigaction() before (or concurrently with) adding whatever call we add here so as to ensure that it will only ever be a ucontext.
>> 
>> Something there is broken in -current, see PR 56471 (freshly compiled macppc
>> ntpd tries to use compat_16___sigreturn14).
> 
> Yes, and from your description it should have failed to register a “sigcontext” handler in the first place.

Martin, is kern.module.autoload enabled on your machine?  (Sorry, my Mac mini is in a state of “has been turned off for a while”, so I need to resurrect it today, so asking for info here to get the investigation going…)

The PowerPC signal trampoline also has a case where it can return EINVAL because it thinks the saved SRR1 has been tampered with.  I’m wondering if somehow the old sigcontext trampoline is getting invoked for a siginfo-style handler.

-- thorpej