[lxc-devel] ramfs userns /proc umount2

Przemyslaw Rudy prudy1 at o2.pl
Wed Jul 29 10:07:19 UTC 2015


/proc/self/mountinfo before the lxc-start:

1 1 0:2 / / rw - rootfs rootfs rw,size=90972k,nr_inodes=22743
13 1 0:5 / /dev rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
14 1 0:4 / /proc rw,relatime - proc proc rw
15 13 0:11 / /dev/pts rw,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=000
16 13 0:13 / /dev/shm rw,relatime - tmpfs tmpfs rw,mode=777
17 1 0:14 / /tmp rw,relatime - tmpfs tmpfs rw
18 1 0:15 / /sys rw,relatime - sysfs sysfs rw
19 18 0:16 / /sys/fs/cgroup rw,relatime - cgroup cgroup rw,cpuset,cpuacct,memory,devices,freezer,net_cls


On 07/29/2015 04:07 AM, Serge Hallyn wrote:
> I suspect you're right and we should simply ignore the failure.
> 
> Can you show /proc/self/mountinfo before the lxc-start?
> 
> Quoting Przemyslaw Rudy (prudy1 at o2.pl):
>> -1 is rv, errno is 22 EINVAL
>>
>> The log:
>>       lxc-start         40.086 INFO     lxc_start_ui - lxc_start.c:main:264 - using rcfile /containers/mycnt/config
>>       lxc-start         40.087 INFO     lxc_confile - confile.c:config_idmap:1376 - read uid map: type u nsid 0 hostid 100000 range 65536
>>       lxc-start         40.087 INFO     lxc_confile - confile.c:config_idmap:1376 - read uid map: type g nsid 0 hostid 100000 range 65536
>>       lxc-start         40.087 WARN     lxc_cgfs - cgfs.c:lxc_cgroup_get_container_info:1100 - Not attaching to cgroup cpuset unknown to /containers mycnt
>>       lxc-start         40.087 DEBUG    lxc_start - start.c:setup_signal_fd:259 - sigchild handler set
>>       lxc-start         40.089 DEBUG    lxc_console - console.c:lxc_console_peer_default:500 - opening /dev/tty for console peer
>>       lxc-start         40.089 DEBUG    lxc_console - console.c:lxc_console_peer_default:506 - using '/dev/tty' as console
>>       lxc-start         40.089 DEBUG    lxc_console - console.c:lxc_console_sigwinch_init:179 - 509 got SIGWINCH fd 9
>>       lxc-start         40.089 DEBUG    lxc_console - console.c:lxc_console_winsz:88 - set winsz dstfd:6 cols:0 rows:0
>>       lxc-start         40.089 INFO     lxc_start - start.c:lxc_init:451 - 'mycnt' is initialized
>>       lxc-start         40.095 DEBUG    lxc_start - start.c:__lxc_start:1137 - Not dropping cap_sys_boot or watching utmp
>>       lxc-start         40.097 INFO     lxc_start - start.c:resolve_clone_flags:848 - Cloning a new user namespace
>>       lxc-start         40.112 DEBUG    lxc_conf - conf.c:instantiate_veth:2703 - instantiated veth 'veth-mycnt/vethNPPNHE', index is '12'
>>       lxc-start         40.112 INFO     lxc_cgroup - cgroup.c:cgroup_init:65 - cgroup driver cgroupfs initing for mycnt
>>       lxc-start         40.122 DEBUG    lxc_conf - conf.c:lxc_assign_network:3120 - move 'eth0' to '512'
>>       lxc-start         40.122 NOTICE   lxc_start - start.c:do_start:667 - switching to gid/uid 0 in new user namespace
>>       lxc-start         40.125 DEBUG    lxc_conf - conf.c:setup_rootfs:1284 - mounted '/containers/mycnt/rootfs' on '/usr/lib/lxc/rootfs'
>>       lxc-start         40.125 INFO     lxc_conf - conf.c:setup_utsname:919 - 'mycnt' hostname has been setup
>>       lxc-start         40.153 DEBUG    lxc_conf - conf.c:setup_netdev:2479 - 'eth0' has been setup
>>       lxc-start         40.153 INFO     lxc_conf - conf.c:setup_network:2500 - network has been setup
>>       lxc-start         40.153 INFO     lxc_conf - conf.c:mount_autodev:1148 - Mounting /dev under /usr/lib/lxc/rootfs
>>       lxc-start         40.153 INFO     lxc_conf - conf.c:mount_autodev:1169 - Mounted tmpfs onto /usr/lib/lxc/rootfs/dev
>>       lxc-start         40.153 INFO     lxc_conf - conf.c:mount_autodev:1187 - Mounted /dev under /usr/lib/lxc/rootfs
>>       lxc-start         40.153 DEBUG    lxc_conf - conf.c:mount_entry:1735 - remounting /shared on /usr/lib/lxc/rootfs/tmp to respect bind or remount optios
>>       lxc-start         40.153 DEBUG    lxc_conf - conf.c:mount_entry:1750 - (at remount) flags for /shared was 0, required extra flags are 0
>>       lxc-start         40.153 DEBUG    lxc_conf - conf.c:mount_entry:1759 - mountflags already was 4098, skipping remount
>>       lxc-start         40.153 DEBUG    lxc_conf - conf.c:mount_entry:1785 - mounted '/shared' on '/usr/lib/lxc/rootfs/tmp', type 'none'
>>       lxc-start         40.153 INFO     lxc_conf - conf.c:mount_file_entries:2034 - mount points have been setup
>>       lxc-start         40.153 INFO     lxc_conf - conf.c:fill_autodev:1215 - Creating initial consoles under /usr/lib/lxc/rootfs/dev
>>       lxc-start         40.153 INFO     lxc_conf - conf.c:fill_autodev:1226 - Populating /dev under /usr/lib/lxc/rootfs
>>       lxc-start         40.154 INFO     lxc_conf - conf.c:fill_autodev:1258 - Populated /dev under /usr/lib/lxc/rootfs
>>       lxc-start         40.154 INFO     lxc_conf - conf.c:setup_dev_console:1515 - console has been setup
>>       lxc-start         40.154 INFO     lxc_conf - conf.c:do_tmp_proc_mount:3576 - I am 1, /proc/self points to ''
>>       lxc-start         40.161 INFO     lxc_conf - conf.c:do_tmp_proc_mount:3602 - Mounted /proc in container for security transition
>>       lxc-start         40.500 ERROR    lxc_conf - conf.c:prepare_ramfs_root:1378 - Invalid argument - Unable to umount /proc
>>       lxc-start         40.500 ERROR    lxc_conf - conf.c:lxc_setup:3917 - failed to set rootfs for 'mycnt'
>>       lxc-start         40.500 ERROR    lxc_start - start.c:do_start:699 - failed to setup the container
>>       lxc-start         40.500 ERROR    lxc_sync - sync.c:__sync_wait:51 - invalid sequence number 1. expected 2
>>       lxc-start         40.500 WARN     lxc_conf - conf.c:lxc_delete_network:2996 - failed to remove interface 'eth0'
>>       lxc-start         40.515 ERROR    lxc_start - start.c:__lxc_start:1164 - failed to spawn 'mycnt'
>>       lxc-start         40.669 ERROR    lxc_start_ui - lxc_start.c:main:344 - The container failed to start.
>>       lxc-start         40.669 ERROR    lxc_start_ui - lxc_start.c:main:348 - Additional information can be obtained by setting the --logfile and --logprio.
>>
>>
>> On 07/28/2015 05:09 PM, Serge Hallyn wrote:
>>> Quoting Przemyslaw Rudy (prudy1 at o2.pl):
>>>> Referring to this patch:
>>>> https://lists.linuxcontainers.org/pipermail/lxc-devel/2014-October/010604.html
>>>>
>>>> Starting lxc with userns in prepare_ramfs_root() I got -1 from:
>>>
>>> rv or errno?
>>>
>>>> if (umount2("./proc", MNT_DETACH)) {
>>>>
>>>> Shall this error be rather ignored in case of userns? Thus the same
>>>> logic as for other mount points processed by mentioned function?
>>>
>>> Can you give full (-l trace -o debug.output) startup log?
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