Segfault in parse_overlay_env when passing graphs option via MANGOHUD_CONFIG

[moody-pantomime]

Describe the bug
Passing graphs options via MANGOHUD_CONFIG environment variable causes segfault.

This seems to happen because parse_overlay_env is called inside parse_overlay_config before the HUDElements.params field is set.

Inside parse_overlay_env, HUDElements.sort_elements is called, where the graphs option has a special case in which HUDElements.params is being accessed. But the field is still nullptr, thus the segfault.

List relevant hardware/software information

• Void
• v0.6.9
• AMD RX6800

To Reproduce
Built MangoHud locally with buildtype=debug, but segfault also happens with release version from Void's repos.

MANGOHUD_CONFIG='graphs=vram' /usr/local/bin/mangohud vkcube
zsh: segmentation fault  MANGOHUD_CONFIG='graphs=vram' /usr/local/bin/mangohud vkcube

Expected behavior
No segfault.

Screenshots
None.

Additional context
None.

[flightlessmango]

Can you post a gdb backtrace of the segfault please?

[moody-pantomime]

Ran with MANGOHUD_CONFIG='graphs=vram' /usr/local/bin/mangohud gdb vkcube

Thread 1 "vkcube" received signal SIGSEGV, Segmentation fault.
HudElements::sort_elements (this=0x7fffeeb5a1e0 <HUDElements>, option={...}) at ../src/hud_elements.cpp:1163
1163	        if (!HUDElements.params->enabled[OVERLAY_PARAM_ENABLED_graphs])
(gdb) bt
#0  HudElements::sort_elements (this=0x7fffeeb5a1e0 <HUDElements>, option={...}) at ../src/hud_elements.cpp:1163
#1  0x00007fffee841a5f in parse_overlay_env (params=0x5555557c8720, env=0x7fffffffe855 "") at ../src/overlay_params.cpp:531
#2  0x00007fffee845c95 in parse_overlay_config (params=0x5555557c8720, env=0x7fffffffe84a "graphs=vram") at ../src/overlay_params.cpp:690
#3  0x00007fffee86f7f1 in overlay_CreateInstance (pCreateInfo=0x7fffffffcc90, pAllocator=0x0, pInstance=0x7fffffffcd48) at ../src/vulkan.cpp:1899
#4  0x00007ffff7adc8bc in ?? () from /usr/lib/libvulkan.so.1
#5  0x00007ffff7ae2c61 in vkCreateInstance () from /usr/lib/libvulkan.so.1
#6  0x0000555555557f01 in ?? ()
#7  0x00007ffff78e320c in __libc_start_call_main (main=main@entry=0x555555557750, argc=argc@entry=1, argv=argv@entry=0x7fffffffe208) at ../sysdeps/nptl/libc_start_call_main.h:58
#8  0x00007ffff78e32bc in __libc_start_main_impl (main=0x555555557750, argc=1, argv=0x7fffffffe208, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffe1f8) at ../csu/libc-start.c:381
#9  0x000055555555a4da in ?? ()
(gdb) print HUDElements.params
$1 = (overlay_params *) 0x0

[shmerl]

I also experienced the segfault.

A side question, why aren't graph options documented in the readme? I couldn't find details on it, except in one of the old release notes.

[flightlessmango]

This shouldn't segfault anymore since 7f94562

why aren't graph options documented in the readme?

Because no one has taken the time to do it

[moody-pantomime]

Works for me now. Thanks!