hyprctl reload full-reset crash in CConfigValueBase::flushCaches()

[KernelFreeze]

Hyprland version

v0.56.1

Is this a regression?

No, it exists since full-reset was introduced in MR #14748

What's the bug?

hyprctl reload full-reset crashed Hyprland with SIGSEGV. The crash report points to:

    CConfigValueBase::flushCaches()

The implementation appears to modify registry() while iterating over it:

void CConfigValueBase::flushCaches() {
    for (const auto& v : registry()) {
        v->bindInternal(v->m_valueName);
    }
}

bindInternal() calls registry().push_back(this). If that reallocates the vector, the iterator used by the loop is invalidated, resulting in undefined behavior. The full-reset handler calls flushCaches() twice.

The same code is still present on main:

• https://github.com/hyprwm/Hyprland/blob/main/src/config/ConfigValue.cpp
• https://github.com/hyprwm/Hyprland/blob/main/src/ipc/s1/Commands.cpp

This appears related to the crashes previously reported under MR #14748:

• hyprctl: add config full-reload for performing a ground-up reload #14748 (comment)
• hyprctl: add config full-reload for performing a ground-up reload #14748 (comment)

Reproduction steps

I issued the command once while debugging a config change.

1. Run hyprctl reload full-reset
2. See it crash (sometimes)

Attachments

hyprlandCrashReport3925.txt

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• I have searched all (open and closed) discussions and issues and my problem is not there.

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[vaxerski]

fixed by #15708