diff options
| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2011-12-09 23:43:47 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-12-11 19:33:19 +0100 |
| commit | 4f89b336fd1edf0c88875d0b7fcdc288c7de903d (patch) | |
| tree | 8cadb7d4c326ad01ce7f0da55db8f03af17917e6 /kernel | |
| parent | Revert "rcu: Permit rt_mutex_unlock() with irqs disabled" (diff) | |
| download | linux-4f89b336fd1edf0c88875d0b7fcdc288c7de903d.tar.xz linux-4f89b336fd1edf0c88875d0b7fcdc288c7de903d.zip | |
rcu: Apply ACCESS_ONCE() to rcu_boost() return value
Both TINY_RCU's and TREE_RCU's implementations of rcu_boost() access
the ->boost_tasks and ->exp_tasks fields without preventing concurrent
changes to these fields. This commit therefore applies ACCESS_ONCE in
order to prevent compiler mischief.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcutiny_plugin.h | 4 | ||||
| -rw-r--r-- | kernel/rcutree_plugin.h | 3 |
2 files changed, 4 insertions, 3 deletions
diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h index dfa97cbb3910..9cb1ae4aabdd 100644 --- a/kernel/rcutiny_plugin.h +++ b/kernel/rcutiny_plugin.h @@ -312,8 +312,8 @@ static int rcu_boost(void) rt_mutex_lock(&mtx); rt_mutex_unlock(&mtx); /* Keep lockdep happy. */ - return rcu_preempt_ctrlblk.boost_tasks != NULL || - rcu_preempt_ctrlblk.exp_tasks != NULL; + return ACCESS_ONCE(rcu_preempt_ctrlblk.boost_tasks) != NULL || + ACCESS_ONCE(rcu_preempt_ctrlblk.exp_tasks) != NULL; } /* diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index f55f10ba01f5..8bb35d73e1f9 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1232,7 +1232,8 @@ static int rcu_boost(struct rcu_node *rnp) rt_mutex_lock(&mtx); /* Side effect: boosts task t's priority. */ rt_mutex_unlock(&mtx); /* Keep lockdep happy. */ - return rnp->exp_tasks != NULL || rnp->boost_tasks != NULL; + return ACCESS_ONCE(rnp->exp_tasks) != NULL || + ACCESS_ONCE(rnp->boost_tasks) != NULL; } /* |