proc_fork_connector: a lockless ->real_parent usage is not safe

[pandora-kernel.git] / drivers / connector / cn_proc.c

diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index 281902d..e55814b 100644 (file)
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -29,7 +29,8 @@
 #include <linux/connector.h>
 #include <linux/gfp.h>
 #include <linux/ptrace.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
+
 #include <asm/unaligned.h>
 
 #include <linux/cn_proc.h>
@@ -56,6 +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;
@@ -66,8 +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;
 
@@ -173,7 +178,6 @@ void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
        struct proc_event *ev;
        struct timespec ts;
        __u8 buffer[CN_PROC_MSG_SIZE];
-       struct task_struct *tracer;
 
        if (atomic_read(&proc_event_num_listeners) < 1)
                return;