Hi, On Wed, 13 Nov 2024 15:05:58 +0100 Chris Hofstaedtler <z...@debian.org> wrote: > util-linux' upstream test suite tests very specific behaviours that > involve the kernel and the underlying filesystem. To avoid broken > tests, the testcases check for the filesystem they run on and skip > tests if they are not prepared to run on a specific filesystem. > > The most problematic filesystem appears to be tmpfs, which is also > the filesystem employed the Debian buildds. > > util-linux' test suite employs findmnt -T $PWD to check the > filesystem. Unfortunately, in sbuild+unshare, this returns nothing. > Apparently, this is because /proc/mounts has no entry for the > directory in which the build runs. > > It would be good if we could a) not duplicate work done already > upstream (f.e. by hunting for these test failures and disabling them > in Debian), and b) not introduce strange cases into the upstream > test suite (building in a directory that has no mount point in > /proc/mounts is certainly "strange"). > > Please see what can be done about this. I'll note that in schroot > this "just works". > > This bug report was triggered by an IRC discussion in #debian-buildd > involving aurel32, josch, jochensp and me. The specific instance > started as https://github.com/util-linux/util-linux/issues/3266 > aka Debian bug #1086706. A previous instance of this is the > "fadvise/count" test, which I've previously marked as known-failing > in unshare, without realizing what the problem was - but it's the > same problem really.
it seems that util-linux worked around this issue in https://github.com/util-linux/util-linux/pull/3282 Nevertheless, the situation is less than ideal. This is how findmnt output looks like inside sbuild unshare: TARGET SOURCE FSTYPE OPTIONS /dev/null udev[/null] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inod /dev/zero udev[/zero] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inod /dev/full udev[/full] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inod /dev/random udev[/random] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inod /dev/urandom udev[/urandom] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inod /dev/tty udev[/tty] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inod /dev/console udev[/console] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inod /dev/pts none devpts rw,nosuid,noexec,relatime,gid=100005,mode=620,ptmxmode=666 /dev/shm tmpfs tmpfs rw,relatime,uid=100000,gid=100000,inode64 /sys sysfs sysfs rw,nosuid,nodev,noexec,relatime ├─/sys/kernel/security │ securityfs securityfs rw,nosuid,nodev,noexec,relatime ├─/sys/fs/cgroup cgroup2 cgroup2 rw,nosuid,nodev,noexec,relatime ├─/sys/fs/pstore pstore pstore rw,nosuid,nodev,noexec,relatime ├─/sys/fs/bpf bpf bpf rw,nosuid,nodev,noexec,relatime,mode=700 ├─/sys/kernel/debug debugfs debugfs rw,nosuid,nodev,noexec,relatime ├─/sys/kernel/tracing │ tracefs tracefs rw,nosuid,nodev,noexec,relatime ├─/sys/kernel/config configfs configfs rw,nosuid,nodev,noexec,relatime ├─/sys/fs/fuse/connections │ fusectl fusectl rw,nosuid,nodev,noexec,relatime └─/sys/kernel tmpfs tmpfs ro,relatime,size=4k,mode=000,uid=100000,gid=100000,inode64 /proc proc proc rw,relatime And this is how it looks like in mmdebstrap in unshare mode: TARGET SOURCE FSTYPE OPTIONS / tmpfs[/mmdebstrap.CihrYkXMBA] │ tmpfs rw,nosuid,nodev,relatime,size=8388608k,inode64 ├─/dev/console │ udev[/console] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inode64 ├─/dev/full udev[/full] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inode64 ├─/dev/null udev[/null] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inode64 ├─/dev/pts none devpts rw,nosuid,noexec,relatime,uid=100005,mode=620,ptmxmode=666 ├─/dev/random udev[/random] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inode64 ├─/dev/shm tmpfs tmpfs rw,nosuid,nodev,inode64 ├─/dev/tty udev[/tty] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inode64 ├─/dev/urandom │ udev[/urandom] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inode64 ├─/dev/zero udev[/zero] devtmpfs rw,nosuid,relatime,size=1780476k,nr_inodes=445119,mode=755,inode64 └─/proc proc proc rw,relatime It is very suboptimal that in sbuild, the root does not show up in /proc/mounts. I do not understand why there is a difference. Both implementations, mmdebstrap as well as sbuild, call this command to mount proc: mount -t proc proc $ROOTFS/proc I do not yet understand what these two implementations do different such that the root mount point is missing in sbuild but present in mmdebstrap... Thanks! cheers, josch
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