From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, oleg@redhat.com, torvalds@linux-foundation.org,
tglx@linutronix.de, ilya.dryomov@inktank.com,
umgwanakikbuti@gmail.com, linux-kernel@vger.kernel.org,
Jiri Slaby <jslaby@suse.cz>
Subject: Re: [RFC][PATCH 5/7] tty: Deal with nested sleeps
Date: Tue, 5 Aug 2014 16:29:16 -0700 [thread overview]
Message-ID: <20140805232916.GC26505@kroah.com> (raw)
In-Reply-To: <20140804103537.628164803@infradead.org>
On Mon, Aug 04, 2014 at 12:30:30PM +0200, Peter Zijlstra wrote:
> n_tty_{read,write} are wait loops with sleeps in. Wait loops rely on
> task_struct::state and sleeps do too, since that's the only means of
> actually sleeping. Therefore the nested sleeps destroy the wait loop
> state and the wait loop breaks the sleep functions that assume
> TASK_RUNNING (mutex_lock).
>
> Fix this by using the new woken_wake_function and wait_woken() stuff,
> which registers wakeups in wait and thereby allows shrinking the
> task_state::state changes to the actual sleep part.
>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Jiri Slaby <jslaby@suse.cz>
> Signed-off-by: Peter Zijlstra <peterz@infradead.org>
> ---
> drivers/tty/n_tty.c | 17 +++++------------
> 1 file changed, 5 insertions(+), 12 deletions(-)
>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
next prev parent reply other threads:[~2014-08-05 23:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-04 10:30 [RFC][PATCH 0/7] nested sleeps, fixes and debug infra Peter Zijlstra
2014-08-04 10:30 ` [RFC][PATCH 1/7] wait: Provide infrastructure to deal with nested blocking Peter Zijlstra
2014-08-04 13:44 ` Peter Zijlstra
2014-08-04 18:35 ` Oleg Nesterov
2014-08-04 10:30 ` [RFC][PATCH 2/7] wait: Provide Peter Zijlstra
2014-08-04 10:30 ` [RFC][PATCH 3/7] exit: Desl with nested sleeps Peter Zijlstra
2014-08-04 18:53 ` Oleg Nesterov
2014-08-04 10:30 ` [RFC][PATCH 4/7] inotify: Deal " Peter Zijlstra
2014-08-04 19:23 ` Oleg Nesterov
2014-08-04 21:02 ` Peter Zijlstra
2014-08-05 2:22 ` Lai Jiangshan
2014-08-05 7:28 ` Peter Zijlstra
2014-08-04 10:30 ` [RFC][PATCH 5/7] tty: " Peter Zijlstra
2014-08-05 23:29 ` Greg Kroah-Hartman [this message]
2014-08-04 10:30 ` [RFC][PATCH 6/7] smp: Correctly deal " Peter Zijlstra
2014-08-04 10:30 ` [RFC][PATCH 7/7] sched: Debug " Peter Zijlstra
2014-08-05 8:33 ` [RFC][PATCH 0/7] nested sleeps, fixes and debug infra Ilya Dryomov
2014-08-05 8:33 ` Ilya Dryomov
2014-08-05 13:06 ` Peter Zijlstra
2014-08-06 7:51 ` Ilya Dryomov
2014-08-06 7:51 ` Ilya Dryomov
2014-08-06 8:31 ` Peter Zijlstra
2014-08-06 21:16 ` David Miller
2014-08-06 21:16 ` David Miller
2014-08-07 8:10 ` Peter Zijlstra
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