/bin/bash: /usr/lib/portage/python3.6/ebuild.sh: permission denied

Доброе утро.
Проблема с системой после обновления профиля до стабильного 17.1 (строго по мануалу, всё шло гладко до 10 пункта, обновить toolchain)
Сломался emerge: при попытке собрать, что-либо выдаёт /bin/bash: /usr/lib/portage/python3.6/ebuild.sh: permission denied
emerge --info
Вот например лог на сборку nano:

#cat /var/tmp/portage/app-editors/nano-3.2/temp/build.log
 * Package:    app-editors/nano-3.2
 * Repository: gentoo
 * Maintainer: 
 * USE:        abi_x86_64 amd64 elibc_glibc kernel_linux magic ncurses nls spell unicode userland_GNU
 * FEATURES:   network-sandbox preserve-libs sandbox userpriv usersandbox
/bin/bash: /usr/lib/portage/python3.6/ebuild.sh: Отказано в доступе
 * The ebuild phase 'unpack' has exited unexpectedly. This type of behavior
 * is known to be triggered by things such as failed variable assignments
 * (bug #190128) or bad substitution errors (bug #200313). Normally, before
 * exiting, bash should have displayed an error message above. If bash did
 * not produce an error message above, it's possible that the ebuild has
 * called `exit` when it should have called `die` instead. This behavior
 * may also be triggered by a corrupt bash binary or a hardware problem
 * such as memory or cpu malfunction. If the problem is not reproducible or
 * it appears to occur randomly, then it is likely to be triggered by a
 * hardware problem. If you suspect a hardware problem then you should try
 * some basic hardware diagnostics such as memtest. Please do not report
 * this as a bug unless it is consistently reproducible and you are sure
 * that your bash binary and hardware are functioning properly.

В целом система жива, то есть прочий софт работает штатно.
Вопрос, как починить emerge? И что собственно сломалось?