Re: [scratch/igc] 985247b6bee crash on Linux, KDE, Wayland

[Pip Cet <pipcet@protonmail.com>]

"Eval EXEC" <execvy@gmail.com> writes:
> Pip Cet <pipcet@protonmail.com> writes:
>> "Eval EXEC" <execvy@gmail.com> writes:
>>> Pip Cet <pipcet@protonmail.com> writes:
>>>> "Eval EXEC" <execvy@gmail.com> writes:
>>>>
>>> I'm useing CPU: 13th Gen Intel(R) Core(TM) i9-13900H (20) @ 5.40 GHz
>>
>> Thanks!  Which gcc version are you using?  Does anyone know how to
>> translate -march=native on that machine to an explicit
>> -march=... argument?
>
> My gcc version is : gcc (GCC) 13.2.0

And that's a -march=raptorlake -mtune=raptorlake CPU, I think.  The
closest I have is a version of GCC 13.3, and that generates what looks
like working code with -march=raptorlake -mtune=raptorlake; it stores an
interior pointer in %r15 while calling the allocation function, which is
stored in _setjmp and should be traced properly.

>>>> I'd recommend these CFLAGS:
>>>>
>>>> -g3 -ggdb -fno-omit-frame-pointer
>>>>
>>>> in addition to what you have.
>>>
>>> Thank you, now I'm going to compile scratch/igc branch by these CFLAGS.
>>>
>>>> Can you disassemble 'copy_font_spec' and 'Flist' by running:
>>>>
>>>> $ gdb /path/to/emacs
>>>> (gdb) disass copy_font_spec
>>>> (gdb) disass Flist
>>>
>>> Sorry, I have deleted the core dump file and the emacs binary.
>>
>> Can you disassemble them in the new emacs binary, that you're building
>> now?  I realize it's possible the code will be different due to the
>> different CFLAGS, but as the crash happened with -fno-omit-frame-pointer
>> there might be something else going on...
>
> emacs on  scratch/igc via ❄️   impure
> ❯ gdb ../emacs-build/scratch_igc/bin/emacs
> GNU gdb (GDB) 14.2
> Copyright (C) 2023 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
> Type "show copying" and "show warranty" for details.
> This GDB was configured as "x86_64-unknown-linux-gnu".
> Type "show configuration" for configuration details.
> For bug reporting instructions, please see:
> <https://www.gnu.org/software/gdb/bugs/>.
> Find the GDB manual and other documentation resources online at:
>     <http://www.gnu.org/software/gdb/documentation/>.
>
> For help, type "help".
> Type "apropos word" to search for commands related to "word"...
> Reading symbols from ../emacs-build/scratch_igc/bin/emacs...
> (gdb) disass copy_font_spec
> Dump of assembler code for function copy_font_spec:
> Address range 0x626760 to 0x62695e:
[...]
> End of assembler dump.
> (gdb)

Those look okay to me.

That's with -O2, right?  Can you try compiling with -O3 and
disassembling those functions to see what the other bug was?

At first glance, the new crash looks like a different bug...

Pip