Package: libgcc-s1 Version: 10-20200202-1 Severity: serious On systems where /lib is a symlink to /usr/lib (which is the case for every new buster installation, for instance), it can easily happen that /usr/lib/$DEB_HOST_MUTIARCH/libgcc_s.so.1 disappears on upgrades. This happens whenever libgcc-s1 is unpacked before the new libgcc1, because the old libgcc1 package ships /lib/$DEB_HOST_MUTIARCH/libgcc_s.so.1 which is in the same place, but unfortunately dpkg does not detect that this means there is a file conflict.
This actually happened to me in a usrmerge chroot, here is the relevant excerpt from dpkg.log: ,---- | # grep libgcc.*1: /var/log/dpkg.log | 2020-02-04 10:02:17 install libgcc-s1:amd64 <none> 10-20200202-1 | 2020-02-04 10:02:17 status half-installed libgcc-s1:amd64 10-20200202-1 | 2020-02-04 10:02:17 status unpacked libgcc-s1:amd64 10-20200202-1 | 2020-02-04 10:02:17 configure libgcc-s1:amd64 10-20200202-1 <none> | 2020-02-04 10:02:17 status unpacked libgcc-s1:amd64 10-20200202-1 | 2020-02-04 10:02:17 status half-configured libgcc-s1:amd64 10-20200202-1 | 2020-02-04 10:02:17 status installed libgcc-s1:amd64 10-20200202-1 | 2020-02-04 10:02:17 upgrade libgcc1:amd64 1:9.2.1-1 1:10-20200202-1 | 2020-02-04 10:02:17 status half-configured libgcc1:amd64 1:9.2.1-1 | 2020-02-04 10:02:17 status unpacked libgcc1:amd64 1:9.2.1-1 | 2020-02-04 10:02:17 status half-installed libgcc1:amd64 1:9.2.1-1 | 2020-02-04 10:02:17 status unpacked libgcc1:amd64 1:10-20200202-1 | 2020-02-04 10:02:17 configure libgcc1:amd64 1:10-20200202-1 <none> | 2020-02-04 10:02:17 status unpacked libgcc1:amd64 1:10-20200202-1 | 2020-02-04 10:02:17 status half-configured libgcc1:amd64 1:10-20200202-1 | 2020-02-04 10:02:17 status installed libgcc1:amd64 1:10-20200202-1 `---- Fortunately "apt reinstall libgcc-s1" remedies the situation, but if the system is rebooted before that, the effects could be more drastic (see #950254 and #950551). -- System Information: Debian Release: bullseye/sid APT prefers unstable APT policy: (500, 'unstable'), (101, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 5.5.1-nouveau (SMP w/2 CPU cores) Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE=de_DE.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system)