From: Dongdong Deng <dongdong.deng@windriver.com>
To: paulmck@linux.vnet.ibm.com, dipankar@in.ibm.com
Cc: linux-kernel@vger.kernel.org, dongdong.deng@windriver.com
Subject: [RFC PATCH] rcu: using ACCESS_ONCE() to observe the jiffies_stall/rnp->qsmask value
Date: Tue, 28 Sep 2010 16:32:43 +0800 [thread overview]
Message-ID: <1285662763-16748-1-git-send-email-dongdong.deng@windriver.com> (raw)
Using ACCESS_ONCE() to observe the jiffies_stall/rnp->qsmask value
due to the caller didn't hold the root_rcu/rnp node's lock.
Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com>
CC: Dipankar Sarma <dipankar@in.ibm.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index d5bc439..07a7063 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -532,9 +532,9 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
if (rcu_cpu_stall_panicking)
return;
- delta = jiffies - rsp->jiffies_stall;
+ delta = jiffies - ACCESS_ONCE(rsp->jiffies_stall);
rnp = rdp->mynode;
- if ((rnp->qsmask & rdp->grpmask) && delta >= 0) {
+ if ((ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && delta >= 0) {
/* We haven't checked in, so go dump stack. */
print_cpu_stall(rsp);
--
1.6.0.4
next reply other threads:[~2010-09-28 8:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-28 8:32 Dongdong Deng [this message]
2010-09-28 23:28 ` Paul E. McKenney
2010-09-29 6:46 ` DDD
2010-10-07 0:43 ` Paul E. McKenney
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