X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=kernel%2Fkthread.c;h=760e86df8c204dc60c23e18b01bdec314780ba1e;hb=91c2e0bcae72a3086c698b5de2b950b885abb0e6;hp=16d8ddd268b1b9c60db1afc6377f72a0754e8d6a;hpb=5a5a1bf099d6942399ea0b34a62e5f0bc4c5c36e;p=firefly-linux-kernel-4.4.55.git

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 16d8ddd268b1..760e86df8c20 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -17,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/freezer.h>
 #include <linux/ptrace.h>
+#include <linux/uaccess.h>
 #include <trace/events/sched.h>
 
 static DEFINE_SPINLOCK(kthread_create_lock);
@@ -135,6 +136,24 @@ void *kthread_data(struct task_struct *task)
 	return to_kthread(task)->data;
 }
 
+/**
+ * probe_kthread_data - speculative version of kthread_data()
+ * @task: possible kthread task in question
+ *
+ * @task could be a kthread task.  Return the data value specified when it
+ * was created if accessible.  If @task isn't a kthread task or its data is
+ * inaccessible for any reason, %NULL is returned.  This function requires
+ * that @task itself is safe to dereference.
+ */
+void *probe_kthread_data(struct task_struct *task)
+{
+	struct kthread *kthread = to_kthread(task);
+	void *data = NULL;
+
+	probe_kernel_read(&data, &kthread->data, sizeof(data));
+	return data;
+}
+
 static void __kthread_parkme(struct kthread *self)
 {
 	__set_current_state(TASK_PARKED);