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Groups > linux.kernel > #1275934
| From | Dave Jones <davej@codemonkey.org.uk> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free |
| Date | 2015-11-23 23:30 +0100 |
| Message-ID | <qy7Mu-7WJ-13@gated-at.bofh.it> (permalink) |
| References | <qy5rm-6jA-71@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Nov 23, 2015 at 02:55:41PM -0500, Tejun Heo wrote:
> A css_set represents the relationship between a set of tasks and
> css's. css_set never pinned the associated css's. This was okay
> because tasks used to always disassociate immediately (in RCU sense) -
> either a task is moved to a different css_set or exits and never
> accesses css_set again.
>
> Unfortunately, afcf6c8b7544 ("cgroup: add cgroup_subsys->free() method
> and use it to fix pids controller") and patches leading up to it made
> a zombie hold onto its css_set and deref the associated css's on its
> release. Nothing pins the css's after exit and it might have already
> been freed leading to use-after-free.
>
> Fix it by making css_set pin the associate css's until its release.
This gets me booting again, thanks Tejun!
Dave
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[PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free Tejun Heo <tj@kernel.org> - 2015-11-23 21:00 +0100
Re: [PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free Dave Jones <davej@codemonkey.org.uk> - 2015-11-23 23:30 +0100
Re: [PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free Daniel Wagner <daniel.wagner@bmw-carit.de> - 2015-11-24 11:40 +0100
Re: [PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free Tejun Heo <tj@kernel.org> - 2015-11-24 15:50 +0100
Re: [PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free Daniel Wagner <daniel.wagner@bmw-carit.de> - 2015-11-24 16:00 +0100
Re: [PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free Tejun Heo <tj@kernel.org> - 2015-11-24 16:00 +0100
Re: [PATCH cgroup/for-4.4-fixes] cgroup: make css_set pin its css's to avoid use-afer-free Tejun Heo <tj@kernel.org> - 2015-11-30 15:50 +0100
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