Re: MPS: a random backtrace while toying with gdb

[Pip Cet]

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...

Pip