[CRIU] Re: [PATCH] reg-files: Serialize linking of ghost files

[Pavel Emelyanov]

On 09/17/2012 02:47 PM, Cyrill Gorcunov wrote:
> On Mon, Sep 17, 2012 at 02:31:18PM +0400, Cyrill Gorcunov wrote:
>> On Mon, Sep 17, 2012 at 02:26:47PM +0400, Pavel Emelyanov wrote:
>>> On 09/17/2012 12:50 PM, Cyrill Gorcunov wrote:
>>>> In case if there at least two tasks with same ghost
>>>> file we've a race in open_path -- both task may enter
>>>> the open_path at same time and try to link ghost file
>>>> to same name leading to
>>>>
>>>>  | 26445: Error (files-reg.c:363): Can't link
>>>>  | /home/crtools/test/zdtm/live/static/write_read10.test (deleted).cr.1.ghost ->
>>>>  | /home/crtools/test/zdtm/live/static/write_read10.test (deleted)
>>>>
>>>> The both tasks have ghost files as
>>>>
>>>>  | id:  0x3 flags: 0x8002 pos: 0000000000000000 ... name: "/home/crtools/test/zdtm/live/static/write_read10.test (deleted)"
>>>>
>>>> and
>>>>
>>>>  | id: 0x10 flags: 0x8002 pos: 0000000000000000 ... name: "/home/crtools/test/zdtm/live/static/write_read10.test (deleted)"
>>>>
>>>> Thus, to serialize link/unlink procedure we use per-ghost-file mutex.
>>>
>>> In that case users can be just unsigned int
>>
>> Yes, but I didn't want to squash everything in one patch. I'll do that on top.
> 
> Here is one on top.

There's a race with two ghosts of the same name.