我从 saucy 更新到了 trusy。
之后，使用sudosegfaulted：
fkalter@London ~> sudo whoami
[sudo] password for fkalter:
YubiKey for `fkalter':
[1] 16961 segmentation fault (core dumped) sudo whoami
因此，当我尝试运行 strace 来获取更多信息时，输出中出现了以下内容：
sudo: effective uid is not 0, is"..., 140sudo: effective uid is not 0, is /usr/bin/sudo on a file system with the 'nosuid' option set or an NFS file system without root privileges?
我的/etc/fstab此时是这样的：
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
UUID=1afaad96-8aa3-4283-95a4-20510e5b3fbb / ext4 rw,async,exec,nouser,suid,errors=remount-ro 0 1
#UUID=1afaad96-8aa3-4283-95a4-20510e5b3fbb / ext4 defaults 0 1
UUID=46605028-51e4-4676-b621-2d8fbab185d5 /boot ext4 defaults 0 2
UUID=8f6af894-fc4a-4a81-b1f7-20c42ef35fe0 /home ext4 defaults 0 2
为了检查我的根文件系统是如何挂载的，我运行了以下命令，mount没有使用任何参数：
fkalter@London ~> mount
/dev/sda6 on / type ext4 (rw)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/cgroup type tmpfs (rw)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
none on /run/user type tmpfs (rw,noexec,nosuid,nodev,size=104857600,mode=0755)
none on /sys/fs/pstore type pstore (rw)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,relatime,cpuset)
cgroup on /sys/fs/cgroup/cpu type cgroup (rw,relatime,cpu,release_agent=/run/cgmanager/agents/cgm-release-agent.cpu)
cgroup on /sys/fs/cgroup/cpuacct type cgroup (rw,relatime,cpuacct,release_agent=/run/cgmanager/agents/cgm-release-agent.cpuacct)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,relatime,memory,release_agent=/run/cgmanager/agents/cgm-release-agent.memory)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,relatime,devices,release_agent=/run/cgmanager/agents/cgm-release-agent.devices)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,relatime,freezer,release_agent=/run/cgmanager/agents/cgm-release-agent.freezer)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,relatime,blkio,release_agent=/run/cgmanager/agents/cgm-release-agent.blkio)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,relatime,perf_event,release_agent=/run/cgmanager/agents/cgm-release-agent.perf_event)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,relatime,hugetlb,release_agent=/run/cgmanager/agents/cgm-release-agent.hugetlb)
/dev/sdf1 on /mnt/secret type ext4 (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/sda5 on /home type ext4 (rw)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
systemd on /sys/fs/cgroup/systemd type cgroup (rw,noexec,nosuid,nodev,none,name=systemd)
/home/fkalter/.Private on /home/fkalter type ecryptfs (ecryptfs_check_dev_ruid,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_unlink_sigs,ecryptfs_sig=153b19c1d2ccc61f,ecryptfs_fnek_sig=03fd342dfcc3e207)
gvfsd-fuse on /run/user/1000/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,user=fkalter)
第一行显示唯一的选项是 rw（读/写）。没有 suid，也没有我在 fstab 中指定的任何其他选项。要查看启动过程中发生的情况，请查看 dmesg 的输出。
fkalter@London ~> dmesg | grep mount
[ 4.445090] EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null)
[ 7.767086] EXT4-fs (sda6): re-mounted. Opts: (null)
[ 7.833123] EXT4-fs (sdf1): mounted filesystem with ordered data mode. Opts: (null)
[ 7.842508] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
[ 7.855840] EXT4-fs (sda5): mounted filesystem with ordered data mode. Opts: (null)
如果我正确执行此操作，则也不会显示任何安装选项。
我怀疑我的 fstab 文件有问题（权限、拼写错误等）。在谷歌上搜索时，唯一的答案似乎是sudo mount -a。最后我的问题是这个。如何在没有 sudo 的情况下检查这一点？