Messages in this thread | | | Date | Thu, 25 Jan 2007 11:36:55 -0600 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH] namespaces: fix race at task exit |
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Quoting Oleg Nesterov (oleg@tv-sign.ru): > On 01/25, Serge E. Hallyn wrote: > > > > In do_exit(), the exit_task_namespaces() was placed after > > exit_notify() because exit_notify ends up using the pid > > namespace both to access the reaper, and for detaching the > > pid. However, this placement allows an nfs server to reap > > the task before exit_task_namespaces() completes. > > > > This patch moves the exit_task_namespaces() into release_task, > > below release_thread() which puts the pids(), and just above > > the call_rcu(delayed_put_task_struct). I believe this should > > solve both problems. > > > > Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> > > > > --- > > > > kernel/exit.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > 765277a4170d7bbd1c4613de661ec6ac64d5580a > > diff --git a/kernel/exit.c b/kernel/exit.c > > index 3540172..ab9ae30 100644 > > --- a/kernel/exit.c > > +++ b/kernel/exit.c > > @@ -174,6 +174,7 @@ repeat: > > write_unlock_irq(&tasklist_lock); > > proc_flush_task(p); > > release_thread(p); > > + exit_task_namespaces(p); > > call_rcu(&p->rcu, delayed_put_task_struct); > > Probably I missed some other patches in this area, but I can't understand > this fix. > > With this change we are doing __put_mnt_ns() when we surely don't have ->sighand, > no? Could you please explain?
Explanation: it's wrong :)
we'll just need to break exit_task_namespaces() up.
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