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  1. 30 9月, 2006 1 次提交
  3. 15 7月, 2006 1 次提交
  5. 28 6月, 2006 1 次提交
  7. 26 6月, 2006 2 次提交
  9. 23 6月, 2006 1 次提交
  11. 30 4月, 2006 1 次提交
  13. 21 3月, 2006 2 次提交
  15. 04 2月, 2006 1 次提交
  17. 11 1月, 2006 1 次提交
  19. 13 12月, 2005 1 次提交
  21. 07 11月, 2005 1 次提交
  23. 17 10月, 2005 1 次提交
    • H
      [PATCH] list: add missing rcu_dereference on first element · b24d18aa
      由 Herbert Xu 提交于 
      It seems that all the list_*_rcu primitives are missing a memory barrier
on the very first dereference.  For example,

#define list_for_each_rcu(pos, head) \
	for (pos = (head)->next; prefetch(pos->next), pos != (head); \
		pos = rcu_dereference(pos->next))

It will go something like:

	pos = (head)->next

	prefetch(pos->next)

	pos != (head)

	do stuff

We're missing a barrier here.

	pos = rcu_dereference(pos->next)

		fetch pos->next

		barrier given by rcu_dereference(pos->next)

		store pos

Without the missing barrier, the pos->next value may turn out to be stale.
In fact, if "do stuff" were also dereferencing pos and relying on
list_for_each_rcu to provide the barrier then it may also break.

So here is a patch to make sure that we have a barrier for the first
element in the list.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: N"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b24d18aa
  25. 30 8月, 2005 4 次提交
  27. 26 6月, 2005 1 次提交
    • P
      [PATCH] RCU: clean up a few remaining synchronize_kernel() calls · b2b18660
      由 Paul E. McKenney 提交于 
      2.6.12-rc6-mm1 has a few remaining synchronize_kernel()s, some (but not
all) in comments.  This patch changes these synchronize_kernel() calls (and
comments) to synchronize_rcu() or synchronize_sched() as follows:

- arch/x86_64/kernel/mce.c mce_read(): change to synchronize_sched() to
  handle races with machine-check exceptions (synchronize_rcu() would not cut
  it given RCU implementations intended for hardcore realtime use.

- drivers/input/serio/i8042.c i8042_stop(): change to synchronize_sched() to
  handle races with i8042_interrupt() interrupt handler.  Again,
  synchronize_rcu() would not cut it given RCU implementations intended for
  hardcore realtime use.

- include/*/kdebug.h comments: change to synchronize_sched() to handle races
  with NMIs.  As before, synchronize_rcu() would not cut it...

- include/linux/list.h comment: change to synchronize_rcu(), since this
  comment is for list_del_rcu().

- security/keys/key.c unregister_key_type(): change to synchronize_rcu(),
  since this is interacting with RCU read side.

- security/keys/process_keys.c install_session_keyring(): change to
  synchronize_rcu(), since this is interacting with RCU read side.
Signed-off-by: N"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b2b18660
  29. 17 4月, 2005 2 次提交