Re: [2.6.33-rc5] starting emacs makes lockdep warning

[AmÃrico Wang]

On Tue, Jan 26, 2010 at 2:07 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Jan 26, 2010 at 02:01:12PM +0800, Am??rico Wang wrote:
>
>> I agree, it seems that patch is useless, since we already
>> do lock_kernel() before calling __f_setown()...
>
> What's to prevent pid from being freed under us? ÂBKL won't...
>

Hmm, I don't fully understand the race here. If it is used to protect
'pid' which we get from 'tty->pgrp' or 'current', in the former case,
it is protected by 'tty->ctrl_lock', in the later case, it doesn't need
the lock. So it's not necessary to protect 'pid' by 'tty->crtl_lock'.

Am i missing something?
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