diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2011-07-28 18:26:32 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-07-28 18:26:32 -0700 |
| commit | 9e8f90dfe58eb19140bc66655170c7aef9eadbf2 (patch) | |
| tree | ebb225345da45a1bdc2384367122aba97f11b308 | |
| parent | 177c27bf05d0ea508e65afdbe4b6998c81e46af5 (diff) | |
proc_fork_connector: a lockless ->real_parent usage is not safe
proc_fork_connector() uses ->real_parent lockless. This is not safe if
copy_process() was called with CLONE_THREAD or CLONE_PARENT, in this case
the parent != current can go away at any moment.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Vladimir Zapolskiy <vzapolskiy@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/connector/cn_proc.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index 3ee1fdb31ea7..e55814bc0d06 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -57,6 +57,7 @@ void proc_fork_connector(struct task_struct *task) struct proc_event *ev; __u8 buffer[CN_PROC_MSG_SIZE]; struct timespec ts; + struct task_struct *parent; if (atomic_read(&proc_event_num_listeners) < 1) return; @@ -67,8 +68,11 @@ void proc_fork_connector(struct task_struct *task) ktime_get_ts(&ts); /* get high res monotonic timestamp */ put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns); ev->what = PROC_EVENT_FORK; - ev->event_data.fork.parent_pid = task->real_parent->pid; - ev->event_data.fork.parent_tgid = task->real_parent->tgid; + rcu_read_lock(); + parent = rcu_dereference(task->real_parent); + ev->event_data.fork.parent_pid = parent->pid; + ev->event_data.fork.parent_tgid = parent->tgid; + rcu_read_unlock(); ev->event_data.fork.child_pid = task->pid; ev->event_data.fork.child_tgid = task->tgid; |