Re: MPS: a random backtrace while toying with gdb

[Eli Zaretskii]

> Date: Sun, 30 Jun 2024 09:59:17 +0000
> From: Pip Cet <pipcet@protonmail.com>
> Cc: Ihor Radchenko <yantar92@posteo.net>, emacs-devel@gnu.org, Eli Zaretskii 
> <eliz@gnu.org>, eller.helmut@gmail.com
> 
> On Saturday, June 29th, 2024 at 21:46, Gerd Möllmann 
> <gerd.moellmann@gmail.com> wrote:
> > Pip Cet pipcet@protonmail.com writes:
> > 
> > > On Saturday, June 29th, 2024 at 19:11, Ihor Radchenko yantar92@posteo.net 
> > > wrote:
> > > 
> > > > I just got this while starting up Emacs on the latest scratch/igc (with
> > > > native-comp).
> > > 
> > > Looks like the same double-signal situation we saw with the profiler, 
> > > only this time it's SIGCHLD interrupting an MPS scan.
> > > 
> > > Pip
> > 
> > 
> > Indeed
> > 
> > #10 0x0000555555827385 in PSEUDOVECTORP (a=XIL(0x7fffeb90875d), code=9) at 
> > /home/yantar92/Git/emacs/src/lisp.h:1105
> > #11 PROCESSP (a=XIL(0x7fffeb90875d)) at 
> > /home/yantar92/Git/emacs/src/process.h:212
> > #12 XPROCESS (a=XIL(0x7fffeb90875d)) at 
> > /home/yantar92/Git/emacs/src/process.h:224
> > #13 handle_child_signal (sig=sig@entry=17) at process.c:7660
> > 
> > Someone has an idea what to do with that? And maybe how to reproduce?
> 
> We could always "steal" the SIGSEGV handler and reinstall it with a sigmask 
> (without modifying the MPS source). My guess is that's equivalent to what the 
> macOS code does, essentially, by using a different class of signal that 
> blocks POSIX signals...

And this is less "ugly" (let alone more safe) than using sigblock?
What am I missing?