[lxc-devel] ramfs userns /proc umount2
Przemyslaw Rudy
prudy1 at o2.pl
Wed Jul 29 14:34:09 UTC 2015
Sure, will do.
The path includes initram and userns, so I suppose its rare.
On 29.07.2015 16:28, Serge Hallyn wrote:
> Ok - if you'd like to send a patch for that that'd be great. I don't have
> any systems where I ever run over that codepath, not sure how many others
> do, so i'm not entirely surprised that noone else has reported this.
>
> thanks,
> -serge
>
> Quoting Przemyslaw Rudy (prudy1 at o2.pl):
>> Yes, commenting out 'return -1' makes it starts and it seems to behave correctly.
>>
>> The /proc/self/mountinfo done from inside the container is empty (as no proc is mounted).
>> If I mount it (by lxc.mount.auto or directly inside the container) then:
>>
>> 42 20 0:2 /containers/mycnt/rootfs / rw - rootfs rootfs rw,size=90972k,nr_inodes=22743
>> 43 42 0:19 / /dev rw,nodev,relatime - tmpfs none rw,size=100k,mode=755,uid=100000,gid=100000
>> 44 43 0:5 /null /dev/null rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
>> 45 43 0:5 /zero /dev/zero rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
>> 46 43 0:5 /full /dev/full rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
>> 47 43 0:5 /urandom /dev/urandom rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
>> 48 43 0:5 /random /dev/random rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
>> 49 43 0:5 /tty /dev/tty rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
>> 50 43 0:5 /console /dev/console rw,relatime - devtmpfs devtmpfs rw,size=90972k,nr_inodes=22743,mode=755
>> 51 50 0:11 /0 /dev/console rw,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=000
>> 52 42 0:2 /shared /tmp rw - rootfs rootfs rw,size=90972k,nr_inodes=22743
>> 30 43 0:20 / /dev/pts rw,relatime - devpts devpts rw,gid=100005,mode=620,ptmxmode=666
>> 31 43 0:20 /0 /dev/tty1 rw,relatime - devpts devpts rw,gid=100005,mode=620,ptmxmode=666
>> 32 42 0:18 / /proc rw,nodev,relatime - proc proc rw
>>
>>
>> BTW. Just to be exact, in first mount log before starting lxc I forgot to enable cloning, so the exact line is:
>> 19 18 0:16 / /sys/fs/cgroup rw,relatime - cgroup cgroup rw,cpuset,cpuacct,memory,devices,freezer,net_cls,clone_children
>> instead of:
>> 19 18 0:16 / /sys/fs/cgroup rw,relatime - cgroup cgroup rw,cpuset,cpuacct,memory,devices,freezer,net_cls
>>
>> On 29.07.2015 15:32, Serge Hallyn wrote:
>>> If you rebuild lxc patching that paragraph to warn but not return
>>> failure when the umount of './proc' fails, does the container start
>>> properly? What does /proc/self/mountinfo inside the container then
>>> look like?
>>>
>>> -serge
>>>
>>> Quoting Przemyslaw Rudy (prudy1 at o2.pl):
>>>> /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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>>>>>>>
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