Messages in this thread | | | Date | Mon, 3 Dec 2012 18:01:25 +0000 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH 3/5] device_cgroup: keep track of local group settings |
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Quoting Aristeu Rozanski (aris@redhat.com): > On Thu, Nov 29, 2012 at 08:26:08PM +0000, Serge E. Hallyn wrote: > > Quoting Aristeu Rozanski (aris@redhat.com): > > > I see your point. it's indeed a problem. in dev_exception_add(), it > > > needs to check for permissions before actually adding to > > > devcgroup->exceptions. > > actually, checked again, it's done correctly. when adding an exception > that will allow extra device access (DEVCG_ALLOW), it does check it > before. It means that you can't add local exceptions unless at a certain > point of the time it was allowed to do so.
Thanks.
...
> git://github.com/aristeu/linux-2.6.git > > please use branch devcg_hiearchy_review
Thanks!
I have a few remaining concerns.
First, generally, I don't think 'allows' added to parent should be automatically propagated to descendents.
In devcgroup_update_access: (around line 625) there is a period of time where cgroup members have default allow without the parent's exceptions.
propagate_behavior (line 505): 1. doesn't follow the same ordering as devcgroup_update_access(), in particular cleaning exceptions before setting behavior. 2. When changing a parent from deny to allow, I don't think children should be updated.
propagate_exception: 1. the WARN_ONCE doesn't seem helpful. 2. Again, I don't think allows to a parent should be propagated, only denies.
-serge
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