Files
odroid-linux/include/linux
Oleg Nesterov 150593bf86 sched/api: Introduce task_rcu_dereference() and try_get_task_struct()
Generally task_struct is only protected by RCU if it was found on a
RCU protected list (say, for_each_process() or find_task_by_vpid()).

As Kirill pointed out rq->curr isn't protected by RCU, the scheduler
drops the (potentially) last reference without RCU gp, this means
that we need to fix the code which uses foreign_rq->curr under
rcu_read_lock().

Add a new helper which can be used to dereference rq->curr or any
other pointer to task_struct assuming that it should be cleared or
updated before the final put_task_struct(). It returns non-NULL
only if this task can't go away before rcu_read_unlock().

( Also add try_get_task_struct() to make it easier to use this API
  correctly. )

Suggested-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
[ Updated comments; added try_get_task_struct()]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Link: http://lkml.kernel.org/r/20160518170218.GY3192@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-03 09:18:57 +02:00
..
2015-10-07 18:08:15 +01:00
2016-03-04 23:50:27 -06:00
2016-05-17 12:29:34 -04:00
2015-05-13 12:04:55 -05:00
2015-12-23 08:37:10 -07:00
2015-03-25 20:28:11 -04:00
2016-03-15 16:55:16 -07:00
2016-02-16 13:04:58 -05:00
2015-02-12 18:54:15 -08:00
2016-05-31 22:12:43 +05:30
2015-01-21 19:21:30 +01:00
2016-05-17 15:48:12 -04:00
2015-06-24 17:49:45 -07:00
2015-12-28 13:41:50 +01:00
2015-03-16 21:45:54 +11:00
2015-05-05 13:40:42 -06:00
2015-11-25 09:22:00 -07:00
2016-04-06 13:18:19 +02:00
2016-03-11 14:58:58 -05:00
2015-10-23 05:44:28 -07:00
2016-02-11 09:59:22 -05:00
2016-03-22 15:36:02 -07:00
2016-05-11 19:31:40 -04:00
2016-05-11 22:37:54 +02:00
2015-06-25 12:06:45 +02:00
2016-05-02 09:32:04 -07:00
2016-01-28 14:19:12 -08:00
2016-03-22 15:36:02 -07:00
2016-03-22 15:36:02 -07:00
2015-07-28 08:50:42 +01:00
2016-01-15 17:56:32 -08:00
2015-04-29 17:17:17 -05:00
2016-03-09 15:43:42 -08:00
2016-05-03 15:07:35 -07:00
2016-01-15 17:56:32 -08:00
2016-05-19 19:12:14 -07:00
2015-10-27 18:55:31 -07:00
2016-05-26 15:35:44 -07:00
2015-06-24 17:49:41 -07:00
2016-05-27 15:57:31 -07:00
2015-10-20 22:10:45 +08:00
2015-07-21 10:39:05 -07:00
2016-05-10 23:56:28 -04:00
2016-05-17 15:48:12 -04:00
2016-05-17 15:47:55 -04:00
2016-05-23 17:04:14 -07:00
2016-04-25 15:09:11 -04:00
2016-02-16 13:04:58 -05:00
2016-05-02 09:00:56 -05:00
2015-03-11 17:56:28 -04:00
2016-05-23 17:04:14 -07:00
2016-05-19 19:12:14 -07:00
2015-09-10 13:29:01 -07:00
2015-04-12 21:03:31 +02:00
2016-02-11 18:35:48 -08:00
2016-02-11 18:35:48 -08:00
2016-03-14 15:43:11 -04:00
2015-01-25 23:17:28 -05:00
2015-10-06 17:08:19 +02:00
2016-02-16 13:04:58 -05:00
2015-10-22 08:59:18 -07:00
2016-03-17 15:09:34 -07:00
2016-03-22 15:36:02 -07:00
2016-03-22 15:36:02 -07:00
2016-03-22 15:36:02 -07:00
2016-01-10 22:13:15 -05:00
2016-05-26 00:04:58 -04:00
2016-01-04 16:11:11 -05:00
2016-05-19 19:12:14 -07:00
2016-05-19 19:12:14 -07:00
2016-05-08 23:46:14 -04:00
2016-05-20 17:58:30 -07:00
2015-06-25 17:00:39 -07:00
2016-05-19 19:12:14 -07:00
2015-10-01 09:57:59 -07:00
2015-10-19 01:01:21 +02:00
2016-05-23 17:04:14 -07:00
2016-04-07 16:53:29 -04:00
2015-11-23 09:44:58 +01:00
2016-05-20 17:58:30 -07:00
2016-02-22 16:10:08 -07:00
2015-12-03 07:24:29 -08:00
2015-03-24 09:48:14 -07:00
2015-09-08 15:35:28 -07:00