From: "Theo de Raadt" <deraadt@openbsd.org>
Subject: Re: Chromium browsers: Meet + webcam = SIGILL?
To: ports@openbsd.org
Date: Mon, 11 Mar 2024 11:14:44 -0600

With a bit of effort, the address you see:

     addr=0x67cb1d220

can be compared in the ktrace to earlier mmap() operations (done by the
shared library linker ld.so); those mmap are mappings against a file descriptor,
and you can see what library file ld.so opened just previously... then we know
what library still has a BTI issue.

Laurence Tratt <laurie@tratt.net> wrote:

> On Mon, Mar 11, 2024 at 12:25:52PM +0000, Stuart Henderson wrote:
> 
> Hello Stuart,
> 
> >> On current, with packages upto date as of Saturday, I get a consistent
> >> SIGILL with Google Meet and the 3 Chromium browsers I'm aware of
> >> (Chromium, Iridium, Ungoogled-Chromium). It seems like it might be
> >> something to do with webcam/video processing in these browsers, but I'm
> >> far from sure.
> >>
> >> To replicate here's what I do:
> >>
> >> 1. Open a new private window (this probably isn't important but force of
> >> habit, but does mean a somewhat more consistent setup).
> >>
> >> 2. Go to meet.google.com and sign in.
> >>
> >> 3. Start a new meeting, and enable both microphone and webcam. As soon
> >> as the main "you should be able to see everyone else screen" is about to
> >> start, I get SIGILL.
> ...
> > Please ktrace and kdump | grep ILL, it should show the type of SIGILL. If
> > you're on Intel 11th gen or newer there's a good chance it will be
> > IBT-related.
> 
> Stuart pointed out off-list that `ktrace -i` is needed. With that I get:
> 
>   69377 chrome   PSIG  SIGILL SIG_DFL code=ILL_BTCFI addr=0x67cb1d220 trapno=21
> 
> I'm not sure if/how to get a backtrace out of any of the Chrome variants...
> 
> 
> Laurie
>