Prev: [PATCH 10/10] drivers: acpi: don't use own implementation of hex_to_bin()
Next: Linux 2.6.34-rc6
From: tip-bot for Paul E. McKenney on 30 Apr 2010 13:10
Commit-ID: 8b46f880841aac821af8efa6581bb0e46b8b9845
Gitweb: http://git.kernel.org/tip/8b46f880841aac821af8efa6581bb0e46b8b9845
Author: Paul E. McKenney <paulmck(a)linux.vnet.ibm.com>
AuthorDate: Wed, 21 Apr 2010 13:02:08 -0700
Committer: Ingo Molnar <mingo(a)elte.hu>
CommitDate: Fri, 30 Apr 2010 12:03:17 +0200

rcu: Fix RCU lockdep splat on freezer_fork path

Add an RCU read-side critical section to suppress this false
positive.

Located-by: Eric Paris <eparis(a)parisplace.org>
Signed-off-by: Paul E. McKenney <paulmck(a)linux.vnet.ibm.com>
Acked-by: Li Zefan <lizf(a)cn.fujitsu.com>
Cc: laijs(a)cn.fujitsu.com
Cc: dipankar(a)in.ibm.com
Cc: mathieu.desnoyers(a)polymtl.ca
Cc: josh(a)joshtriplett.org
Cc: dvhltc(a)us.ibm.com
Cc: niv(a)us.ibm.com
Cc: peterz(a)infradead.org
Cc: rostedt(a)goodmis.org
Cc: Valdis.Kletnieks(a)vt.edu
Cc: dhowells(a)redhat.com
Cc: eric.dumazet(a)gmail.com
LKML-Reference: <1271880131-3951-2-git-send-email-paulmck(a)linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo(a)elte.hu>
---
kernel/cgroup_freezer.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index da5e139..e5c0244 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -205,9 +205,12 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
* No lock is needed, since the task isn't on tasklist yet,
* so it can't be moved to another cgroup, which means the
* freezer won't be removed and will be valid during this
- * function call.
+ * function call. Nevertheless, apply RCU read-side critical
+ * section to suppress RCU lockdep false positives.
*/
+ rcu_read_lock();
freezer = task_freezer(task);
+ rcu_read_unlock();

/*
* The root cgroup is non-freezable, so we can skip the
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: [PATCH 10/10] drivers: acpi: don't use own implementation of hex_to_bin()
Next: Linux 2.6.34-rc6