Package: schroot Version: 1.6.13-3+b2 Severity: important X-Debbugs-Cc: i...@ilbers.de, ub...@ilbers.de
Hello! I have multiple schroot instances running in parallel. Some of them are started by sbuild, others have been started manually by scripts. All those schroot instances are sharing the same chroot and session config directories (/etc/schroot/chroot.d and /var/lib/schroot/session). When any single schroot is running, it starts with parsing all the files in config directories. As reading file list and opening every config file are separate operations with no locking or any way to make it atomic, other schroot instance can stop session and remove corresponding config file between this operations. It makes the first instance fail with: E: /var/lib/schroot/session/<session2_id>: Failed to stat file: No such file or directory or E: /var/lib/schroot/session/<session2_id>: Failed to open file: No such file or directory depends on which stage it was deleted (before stat or between stat and open operations). The only locking currently done is on config file content parsing which is not enough for such a case. The same issue is observed on chroot config files when deleting any chroot config externally. There are two ways of fixing this issue: 1. Do not fail on file operations if file not exists. Don't look like the correct way, but easy to implement. 2. Cover both file list obtaining and files opening with a lock. Locking in chroot_config::add_config_directory() calls can be shared, while sbuild::chroot::setup_session_info should use exclusive mode. This lockfile can be accessible by external applications to allow safe chroot config files removing. Solution proposed upstream: https://codeberg.org/shelter/reschroot/pulls/11 -- System Information: Debian Release: 12.8 APT prefers stable APT policy: (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 6.11.5+bpo-amd64 (SMP w/32 CPU threads; PREEMPT) Locale: LANG=C.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set Shell: /bin/sh linked to /usr/bin/dash Init: unable to detect Versions of packages schroot depends on: ii debconf [debconf-2.0] 1.5.82 ii libboost-filesystem1.74.0 1.74.0+ds1-21 ii libboost-iostreams1.74.0 1.74.0+ds1-21 ii libboost-program-options1.74.0 1.74.0+ds1-21 ii libc6 2.36-9+deb12u9 ii libgcc-s1 12.2.0-14 ii libpam0g 1.5.2-6+deb12u1 ii libstdc++6 12.2.0-14 ii libuuid1 2.38.1-5+deb12u2 ii schroot-common 1.6.13-3 ii sysvinit-utils [lsb-base] 3.06-4 schroot recommends no packages. Versions of packages schroot suggests: pn aufs-tools | unionfs-fuse <none> pn btrfs-progs <none> ii bzip2 1.0.8-5+b1 ii debootstrap 1.0.128+nmu2+deb12u1 pn lvm2 <none> ii qemu-user-static 1:7.2+dfsg-7+deb12u7 ii xz-utils 5.4.1-0.2 pn zfsutils-linux <none> ii zstd 1.5.4+dfsg2-5 -- debconf information: schroot/bad-names:
