Messages in this thread | | | Date | Tue, 10 Feb 2009 12:45:27 +0000 | From | Al Viro <> | Subject | Re: [PATCH] cgroups: fix possible use after free |
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On Tue, Feb 10, 2009 at 02:15:36AM -0800, Paul Menage wrote: > On Tue, Feb 10, 2009 at 1:31 AM, Li Zefan <lizf@cn.fujitsu.com> wrote: > > In cgroup_kill_sb(), root is freed before sb is detached from the list, > > so another sget() may find this sb and call cgroup_test_super(), > > which will access the root that has been freed. > > I think that I'd assumed that by the time we get to cgroup_kill_sb() > there's no chance of the sb being resurrected by sget().
There is none. grab_super() will fail to get it, so sget() will go through retry logics. Which doesn't mean that test won't be called on it in the meanwhile.
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