Subject: bug#75292: 31.0.50; igc: (file-error "Doing vfork" "Bad address")

From: Pip Cet <[email-masked]>
Date: Thu, 02 Jan 2025 20:45:40 +0000

"Ihor Radchenko" <[email-masked]> writes:

> I am getting the belo error regularly, when Emacs is spawning external
> process. Not every time though.

Sounds like something's moved by GC and shouldn't be.  Since you're
running without optimization, it's unlikely that GCC (we don't indicate
the compiler used in report-emacs-bug?  we should) mangled a reference
badly.

The code does assume that SAFE_ALLOCA'd string pointers keep the string
data alive.  That is a bug, and it might cause the behavior you see if,
for some weird reason, we wouldn't be using alloca directly.  But I
think we would be, unless there is something odd about your system.

> See the full backtrace below.
> Please advice what I can do to debug further.

After checking Eli's suggestion, an strace would be nice to find out
which of the pointers has gone bad.

FWIW, I'll try reproducing this now, using your build flags...

Pip