[CRIU] [PATCH] mount: handle a circular reference in mount tree

[Christopher Covington]

On 09/15/2014 08:23 AM, Pavel Emelyanov wrote:
> On 09/12/2014 03:41 PM, Andrey Vagin wrote:
>> $ cat /proc/self/mountinfo
>> ...
>> 1 1 0:2 / / rw - rootfs rootfs rw,size=373396k,nr_inodes=93349
>> ...
>>
>> You can see that mnt_id and parent_mnt_id are equals here.
>> This patch interpretes this case as a root mount in a tree.
> 
> While I agree with the patch, I'd like to get some info about
> how this all happens from the kernel objects perspective.
> 
> The kernel's show_mountinfo() prints this like
> seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
> 
> which means, that each mnt always has a parent.
> 
> We've typically seen the 0 as root's parent. Where did the kernel
> get this mount from?

I've only seen this happen on the initramfs.

Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.