Re: [RESEND PATCH] pid_ns: Fix proc_flush_task() accessing freedproc_mnt

From: Oleg Nesterov
Date: Fri Jun 25 2010 - 15:31:48 EST


On 06/25, Sukadev Bhattiprolu wrote:
>
> Louis Rilling [Louis.Rilling@xxxxxxxxxxx] wrote:
> | - proc_pid_readdir():
> | Needs similar check and protection to proc_pid_lookup(), but there is another
> | issue: next_tgid() can find a dying task:
>
> Hmm, I thought proc_pid_readdir() would be a problem too but convinced myself
> that it would not - since a process running proc_pid_readdir() would have
> a reference to the pid namespace,

Where does this reference comes from ?

proc_pid_readdir() pins the task_struct (ns->child_reaper), not the pid/ns.

But I won't be surprised if I am wrong again ;)

Oleg.

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