pachi: Crash on startup

[smcv]

Prerequisites:

• Debian testing (Debian 12 alpha)
• Video: GNOME 43 in Wayland mode (with Mesa 22.2.0 on AMD Vega, if it matters)
• Audio: Pipewire 0.3.59, with pipewire-pulse emulating PulseAudio
• apt install pachi (Debian package version 1:1.0-10)
• Some relevant libraries:
  • libsdl1.2-compat either 1.2.58-1 (packaged in Debian experimental) or commit 63e4393 (locally built)
  • libsdl2-2.0-0 version 2.24.1+dfsg-1
  • libsdl-mixer1.2 version 1.2.12-17+b2
  • libsdl1.2debian (real SDL 1.2) version 1.2.15+dfsg2-8

To reproduce:

• ld.so /usr/games/pachi
• LD_LIBRARY_PATH=.../sdl12-compat/_build ld.so /usr/games/pachi
• SDL_VIDEODRIVER=wayland LD_LIBRARY_PATH=.../sdl12-compat/_build ld.so /usr/games/pachi

Expected result: it runs

Actual result: real SDL 1.2 works. sdl12-compat segfaults on startup with a very unhelpful stack trace (it seems debuginfod.debian.net doesn't have access to its debug symbols):

#0  0x00007fcbda72b25f in  ()
#1  0x00007ffc71daafa8 in  ()
#2  0x00007fcbda72b31f in  ()
#3  0x00007fcbda7273d0 in  ()
#4  0x0000000000000000 in  ()

[smcv]

I'm going to continue testing other games rather than focusing on this one, but let me know if you'd like me to do a rebuild with debug symbols so we can get a useful stack trace.

[icculus]

but let me know if you'd like me to do a rebuild with debug symbols so we can get a useful stack trace.

I did it (I'm probably going to need it locally anyhow, and "apt-get source pachi" makes this easy enough.)

Thread 1 "pachi" received signal SIGSEGV, Segmentation fault.
0x000055555555c04c in init_intro () at /home/icculus/pachi-1.0/src/intro.c:33
33      SDL_FillRect(temp, NULL, SDL_MapRGB(temp->format,0,0,0));
(gdb) bt
#0  0x000055555555c04c in init_intro() () at /home/icculus/pachi-1.0/src/intro.c:33
#1  0x000055555555c13b in intro() () at /home/icculus/pachi-1.0/src/intro.c:51
#2  0x00005555555634b6 in main(int, char**) (argc=1, argv=0x7fffffffe008) at faes.cpp:66

[icculus]

temp is NULL here, hence the crash in the game and not sdl12-compat.

Created on the line before:

temp=SDL_CreateRGBSurface(SDL_SWSURFACE, screen_w, screen_h, screen_bpp, 255, 255, 255, 0);

screen_w, screen_h and screen_bpp are 800, 600, and 16, respectively.

[icculus]

I guess the bogus masks are what causes this. This is a different angle on the same thing rockdodger does: a bogus surface that they immediately convert with SDL_DisplaySurface.

[smcv]

Confirmed fixed by https://github.com/libsdl-org/sdl12-compat/commit/67f8b3a85b782eefb4db90f34d5b0742ef2cb5fc, 1.2.58 + 29 commits