After upgrading to dnf-2.7.3-1 and related DNF packages, livecd-creator consistently crashes with a python error: *** Error in `/usr/bin/python3': free(): invalid pointer: 0x00007f4cca6c3e40 *** Downgrading dnf to the previous release fixes it.
Noticed that this also affects F27 devel with dnf version dnf-2.7.2-1.fc27 and I can't seem to downgrade it... so I can't fix the issue. Getting this error when running livecd-creator: *** Error in `/usr/bin/python3': free(): invalid pointer: 0x00007f78d6ec5e40 ***
Downgrading F27 devel to the following package versions, made livecd-creator work again: dnf-2.6.3-12.fc27.noarch.rpm dnf-conf-2.6.3-12.fc27.noarch.rpm dnf-plugins-core-2.1.3-2.fc27.noarch.rpm dnf-yum-2.6.3-12.fc27.noarch.rpm libdnf-0.9.3-7.fc27.x86_64.rpm python2-dnf-2.6.3-12.fc27.noarch.rpm python2-hawkey-0.9.3-7.fc27.x86_64.rpm python3-dnf-2.6.3-12.fc27.noarch.rpm python3-dnf-plugins-core-2.1.3-2.fc27.noarch.rpm python3-hawkey-0.9.3-7.fc27.x86_64.rpm
Looks like this is a duplicate of bug 1498207. I'll see if the fix given there resolves this issue too.
Updating to libdnf-0.11.0-1 in both F26 and F27 fixes the problem.
*** This bug has been marked as a duplicate of bug 1498207 ***