[CRIU] Fake mount points in dump

[Stanislav Kinsburskiy]

19.01.2016 16:44, Pavel Emelyanov пишет:
> On 01/19/2016 05:54 PM, Stanislav Kinsburskiy wrote:
>>
>> 19.01.2016 13:28, Pavel Emelyanov пишет:
>>> On 01/19/2016 01:46 PM, Stanislav Kinsburskiy wrote:
>>>> 18.01.2016 17:26, Pavel Emelyanov пишет:
>>>>> On 01/18/2016 03:35 PM, Stanislav Kinsburskiy wrote:
>>>>>> Hi,
>>>>>>
>>>>>> I'm trying to suspend a container with the following mount list in it:
>>>>>>
>>>>>> [root at centos-7-x86_64 ~]# cat /proc/mounts
>>>>>> rootfs / rootfs rw 0 0
>>>>>> /dev/ploop43992p1 / ext4 rw,relatime,data=ordered,balloon_ino=12 0 0
>>>>>> none /sys sysfs rw,relatime,ve=102 0 0
>>>>>> none /sys/fs/cgroup tmpfs rw,relatime,size=1931780k,nr_inodes=482945 0 0
>>>>>> cgroup /sys/fs/cgroup/cpuset cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,cpuset 0 0
>>>>>> cgroup /sys/fs/cgroup/cpu,cpuacct cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,cpuacct,cpu 0 0
>>>>>> cgroup /sys/fs/cgroup/memory cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,memory 0 0
>>>>>> cgroup /sys/fs/cgroup/devices cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,devices 0 0
>>>>>> cgroup /sys/fs/cgroup/freezer cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,freezer 0 0
>>>>>> cgroup /sys/fs/cgroup/net_cls cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,net_cls 0 0
>>>>>> cgroup /sys/fs/cgroup/blkio cgroup rw,nosuid,nodev,noexec,relatime,blkio 0 0
>>>>>> cgroup /sys/fs/cgroup/perf_event cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,perf_event 0 0
>>>>>> cgroup /sys/fs/cgroup/hugetlb cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,hugetlb 0 0
>>>>>> cgroup /sys/fs/cgroup/systemd cgroup
>>>>>> rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd
>>>>>> 0 0
>>>>>> proc /proc proc rw,relatime 0 0
>>>>>> devtmpfs /dev devtmpfs rw,nosuid,size=1931780k,nr_inodes=482945 0 0
>>>>>> tmpfs /dev/shm tmpfs rw,nosuid,nodev 0 0
>>>>>> devpts /dev/pts devpts
>>>>>> rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
>>>>>> tmpfs /run tmpfs rw,nosuid,nodev,mode=755 0 0
>>>>>> mqueue /dev/mqueue mqueue rw,relatime 0 0
>>>>>> sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw,relatime 0 0
>>>>>>
>>>>>> and get the following error (persistent):
>>>>>>
>>>>>> (00.221054) mnt: <--
>>>>>> (00.221489)     type proc source proc mnt_id 20 s_dev 0x3 / @ ./proc
>>>>>> flags 0x30000e options
>>>>>> (00.221651)     type sysfs source sysfs mnt_id 21 s_dev 0x13 / @ ./sys
>>>>>> flags 0x30000e options
>>>>>> (00.221754)     type devtmpfs source devtmpfs mnt_id 22 s_dev 0x5 / @
>>>>>> ./dev flags 0x1100000 options size=1922508k,nr_inodes=480627,mode=755
>>>>>> (00.221842)     type securityfs source securityfs mnt_id 23 s_dev 0x14 /
>>>>>> @ ./sys/kernel/security flags 0x30000e options
>>>>>> (00.221927)     type tmpfs source tmpfs mnt_id 24 s_dev 0x15 / @
>>>>>> ./dev/shm flags 0x1100000 options
>>>>>> (00.222015)     type devpts source devpts mnt_id 25 s_dev 0xb / @
>>>>>> ./dev/pts flags 0x30000a options gid=5,mode=620,ptmxmode=000
>>>>>> (00.222163)     type tmpfs source tmpfs mnt_id 26 s_dev 0x16 / @ ./run
>>>>>> flags 0x1100000 options mode=755
>>>>>> (00.222624)     type tmpfs source tmpfs mnt_id 27 s_dev 0x17 / @
>>>>>> ./sys/fs/cgroup flags 0x1100000 options mode=755
>>>>>> (00.222716)     type cgroup source cgroup mnt_id 28 s_dev 0x18 / @
>>>>>> ./sys/fs/cgroup/systemd flags 0x30000e options
>>>>>> xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd
>>>>>> (00.222803)     type pstore source pstore mnt_id 29 s_dev 0x19 / @
>>>>>> ./sys/fs/pstore flags 0x30000e options
>>>>>> (00.222917)     type cgroup source cgroup mnt_id 30 s_dev 0x12 / @
>>>>>> ./sys/fs/cgroup/cpuset flags 0x30000e options cpuset
>>>>>> (00.223022)     type cgroup source cgroup mnt_id 31 s_dev 0x11 / @
>>>>>> ./sys/fs/cgroup/cpu,cpuacct flags 0x30000e options cpuacct,cpu
>>>>>> (00.223147)     type cgroup source cgroup mnt_id 32 s_dev 0xf / @
>>>>>> ./sys/fs/cgroup/memory flags 0x30000e options memory
>>>>>> (00.223303)     type cgroup source cgroup mnt_id 33 s_dev 0x1a / @
>>>>>> ./sys/fs/cgroup/devices flags 0x30000e options devices
>>>>>> (00.223425)     type cgroup source cgroup mnt_id 34 s_dev 0x1b / @
>>>>>> ./sys/fs/cgroup/freezer flags 0x30000e options freezer
>>>>>> (00.223514)     type cgroup source cgroup mnt_id 35 s_dev 0x1c / @
>>>>>> ./sys/fs/cgroup/net_cls flags 0x30000e options net_cls
>>>>>> (00.223602)     type cgroup source cgroup mnt_id 36 s_dev 0xe / @
>>>>>> ./sys/fs/cgroup/blkio flags 0x30000e options blkio
>>>>>> (00.223688)     type cgroup source cgroup mnt_id 37 s_dev 0x1d / @
>>>>>> ./sys/fs/cgroup/perf_event flags 0x30000e options perf_event
>>>>>> (00.223773)     type cgroup source cgroup mnt_id 38 s_dev 0x1e / @
>>>>>> ./sys/fs/cgroup/hugetlb flags 0x30000e options hugetlb
>>>>>> (00.223858)     type cgroup source cgroup mnt_id 39 s_dev 0x1f / @
>>>>>> ./sys/fs/cgroup/ve flags 0x30000e options ve
>>>>>> (00.224002)     type cgroup source cgroup mnt_id 40 s_dev 0x10 / @
>>>>>> ./sys/fs/cgroup/beancounter flags 0x30000e options beancounter
>>>>>> (00.224116)     type configfs source configfs mnt_id 43 s_dev 0x20 / @
>>>>>> ./sys/kernel/config flags 0x300000 options
>>>>>> (00.224274)     type ext4 source /dev/mapper/vz_skinsbursky--vz7-root
>>>>>> mnt_id 44 s_dev 0xfd00001 / @ ./ flags 0x300000 options
>>>>>> quota,usrquota,grpquota,data=ordered
>>>>>> (00.224387)     type autofs source systemd-1 mnt_id 45 s_dev 0x21 / @
>>>>>> ./proc/sys/fs/binfmt_misc flags 0x300000 options
>>>>>> fd=32,pgrp=1,timeout=300,minproto=5,maxproto=5,direct
>>>>>> (00.224485) Error (autofs.c:220): Failed to find pipe_ino option (old
>>>>>> kernel?)
>>>>>> (00.224565) Error (proc_parse.c:1385): Failed to parse FS specific data
>>>>>> on ./proc/sys/fs/binfmt_misc
>>>>>> (00.224686) Error (mount.c:1908): mnt: Can't parse 83507's mountinfo
>>>>>> (00.224770) Error (mount.c:824): mnt: Failed to find criu pid's mount ns
>>>>> This error only appear if you use --ext-mount-map auto, do you?
>>>> Yes, above is correct.
>>>> What does it mean?
>>> It means than any external bind-mounts are tried to get auto-resolved.
>>> Your error means that either a) we don't have such, but they are erroneously
>>> detected or b) we have such, they are auto-detected by parsing host's
>>> mount points and latter contain unsupported entries. In the latter case
>>> we can fix it by relaxing the requirement for host's mountpoints e.g.
>>> we can ignore options, since we don't need them.
>> This is probably the former case.
>> If I shutdown autofs service on host, dump succeeds.
>> One more question: what makes you think, that it's the former case?
> I didn't tell I thought this was the former case.
>
>> Who or what can bind-mount service mount to a container?
> This can be done by vzctl or by kernel propagation, but I don't
> know whether this is the case.
>
> Looking at the resolve_external_mounts() I see that we parse host's
> mountpoints regardless of whether we have ext mounts or not. So I
> withdraw my previous comment and make new statement: host's mount
> points contain unsupported entries, but we "fail in advance" w/o
> actually checking whether we need them at all.

This message:

(00.122918)     type autofs source systemd-1 mnt_id 86 s_dev 0x2e / @ 
./proc/sys/fs/binfmt_misc flags 0x300000 options 
fd=43,pgrp=1,timeout=300,minproto=5,maxproto=5,direct

is printed in parse_mountinfo(). Thus this information comes from kernel.
It looks strange to me, that mount_info of criu process contains 
container's mount points + autofs from host.
Isn't it?


> -- Pavel