Subject: bug#79131: 31.0.50; igc: nested signal, SIGSEGV

From: Óscar Fuentes <[email-masked]>
Date: Sun, 03 Aug 2025 16:46:47 +0200

Pip Cet <[email-masked]> writes:

> So can you try
>     p current_buffer->pt

(gdb) fr 13
#13 0x000055e77414774b in Fadd_text_properties (start=0x1f06a, end=0x1f07a, properties=<optimized out>, 
    object=0x0) at ../../emacs/src/textprop.c:1308
1308      return add_text_properties_1 (start, end, properties, object,
(gdb) p current_buffer->pt
$1 = 5961

>     p *XSTRING(current_buffer->name_)

(gdb) p *XSTRING(current_buffer->name_)
No symbol "XSTRING" in current context.

>     p current_buffer->beg + 1153

(gdb) p current_buffer->beg + 1153
There is no member named beg.
(gdb) p current_buffer->text->beg + 1153
$3 = (unsigned char *) 0x55e77e158401 <first lines of buffer>

>     p current_buffer->beg + 1153 + 31770 - 64

(gdb) p current_buffer->text->beg + 1153 + 31770 - 64
$4 = (unsigned char *) 0x55e77e15ffdb <last lines of buffer>

Actually:

(gdb) p current_buffer->text->beg + 1153 + 31770
$6 = (unsigned char *) 0x55e77e16001b

shows the last 22 characters of the buffer without garbage at the end.
It doesn't look like a buffer overrun.

Probably you are right and this is not a MPS-related crash.