From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com,
bobby.prani@gmail.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 4/4] list: Use WRITE_ONCE() when initializing list_head structures
Date: Fri, 4 Dec 2015 16:15:31 -0800 [thread overview]
Message-ID: <1449274531-27043-4-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <20151205001505.GA26649@linux.vnet.ibm.com>
Code that does lockless emptiness testing of non-RCU lists is relying
on INIT_LIST_HEAD() to write the list head's ->next pointer atomically,
particularly when INIT_LIST_HEAD() is invoked from list_del_init().
This commit therefore adds WRITE_ONCE() to this function's pointer stores
that could affect the head's ->next pointer.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/list.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/list.h b/include/linux/list.h
index 06c2d887a918..5356f4d661a7 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -24,7 +24,7 @@
static inline void INIT_LIST_HEAD(struct list_head *list)
{
- list->next = list;
+ WRITE_ONCE(list->next, list);
list->prev = list;
}
--
2.5.2
prev parent reply other threads:[~2015-12-05 0:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-05 0:15 [PATCH tip/core/rcu 0/4] linked-list updates for 4.5 Paul E. McKenney
2015-12-05 0:15 ` [PATCH tip/core/rcu 1/4] list: Use WRITE_ONCE() when adding to lists and hlists Paul E. McKenney
2015-12-05 0:15 ` [PATCH tip/core/rcu 2/4] list: Use READ_ONCE() when testing for empty lists Paul E. McKenney
2015-12-05 0:15 ` [PATCH tip/core/rcu 3/4] list: Introduces generic list_splice_tail_init_rcu() Paul E. McKenney
2015-12-05 0:15 ` Paul E. McKenney [this message]
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