From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
eric.dumazet@gmail.com
Subject: [PATCH tip/core/urgent] rcu: rcu_read_lock_bh_held(): disabling irqs also disables bh
Date: Wed, 22 Sep 2010 17:32:20 -0700 [thread overview]
Message-ID: <20100923003220.GA21822@linux.vnet.ibm.com> (raw)
rcu_dereference_bh() doesnt know yet about hard irq being disabled, so
lockdep can trigger in netpoll_rx() after commit f0f9deae9e7c4 (netpoll:
Disable IRQ around RCU dereference in netpoll_rx)
Reported-by: Miles Lane <miles.lane@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Miles Lane <miles.lane@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/rcupdate.h | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 9fbc54a..0dcc00e 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -454,7 +454,8 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* Makes rcu_dereference_check() do the dirty work.
*/
#define rcu_dereference_bh(p) \
- rcu_dereference_check(p, rcu_read_lock_bh_held())
+ rcu_dereference_check(p, rcu_read_lock_bh_held() || \
+ irqs_disabled())
/**
* rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched
--
1.7.0.6
next reply other threads:[~2010-09-23 0:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-23 0:32 Paul E. McKenney [this message]
2010-09-23 1:34 ` [PATCH tip/core/urgent] rcu: rcu_read_lock_bh_held(): disabling irqs also disables bh Lai Jiangshan
2010-09-23 3:15 ` Paul E. McKenney
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