Messages in this thread | | | Date | Tue, 26 Jan 2010 06:54:26 +0000 | From | Al Viro <> | Subject | Re: [2.6.33-rc5] starting emacs makes lockdep warning |
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On Tue, Jan 26, 2010 at 02:24:30PM +0800, Am??rico Wang wrote: > On Tue, Jan 26, 2010 at 2:07 PM, Al Viro <viro@zeniv.linux.org.uk> 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? ??BKL 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 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Without that patch it isn't.
> the lock. So it's not necessary to protect 'pid' by 'tty->crtl_lock'.
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