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authorTejun Heo <tj@kernel.org>2013-08-13 17:01:54 +0200
committerTejun Heo <tj@kernel.org>2013-08-13 17:01:54 +0200
commitb77d7b6088377998ebf65eaea5e51008c2d75e94 (patch)
treecab54dcd2c0639b127eb7920f6459d5f84695da0 /kernel/events
parentcgroup: add cgroup_subsys_state->parent (diff)
downloadlinux-b77d7b6088377998ebf65eaea5e51008c2d75e94.tar.xz
linux-b77d7b6088377998ebf65eaea5e51008c2d75e94.zip
cgroup: cgroup_css_from_dir() now should be called with RCU read locked
cgroup->subsys[] will become RCU protected and thus all cgroup_css() usages should either be under RCU read lock or cgroup_mutex. This patch updates cgroup_css_from_dir() which returns the matching cgroup_subsys_state given a directory file and subsys_id so that it requires RCU read lock and updates its sole user perf_cgroup_connect(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c199c4f24910..23261f957713 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -591,6 +591,8 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event,
if (!f.file)
return -EBADF;
+ rcu_read_lock();
+
css = cgroup_css_from_dir(f.file, perf_subsys_id);
if (IS_ERR(css)) {
ret = PTR_ERR(css);
@@ -617,6 +619,7 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event,
ret = -EINVAL;
}
out:
+ rcu_read_unlock();
fdput(f);
return ret;
}