Messages in this thread Patch in this message | | | Date | Thu, 22 Apr 2010 17:30:40 +0800 | From | Li Zefan <> | Subject | [PATCH 3/5] sched: Fix an RCU warning in print_task() |
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With CONFIG_PROVE_RCU=y, a warning can be triggered:
$ cat /proc/sched_debug
... kernel/cgroup.c:1649 invoked rcu_dereference_check() without protection! ...
Both cgroup_path() and task_group() should be called with either rcu_read_lock or cgroup_mutex held.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> --- kernel/sched_debug.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 9cf1baf..87a330a 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -114,7 +114,9 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) { char path[64]; + rcu_read_lock(); cgroup_path(task_group(p)->css.cgroup, path, sizeof(path)); + rcu_read_unlock(); SEQ_printf(m, " %s", path); } #endif -- 1.6.3
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