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Diffstat (limited to 'kernel/kthread.c')
-rw-r--r--kernel/kthread.c31
1 files changed, 14 insertions, 17 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 4388d6694a7f..8e5f44bed027 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -93,20 +93,27 @@ static inline struct kthread *__to_kthread(struct task_struct *p)
return kthread;
}
-void set_kthread_struct(struct task_struct *p)
+bool set_kthread_struct(struct task_struct *p)
{
struct kthread *kthread;
- if (__to_kthread(p))
- return;
+ if (WARN_ON_ONCE(to_kthread(p)))
+ return false;
kthread = kzalloc(sizeof(*kthread), GFP_KERNEL);
+ if (!kthread)
+ return false;
+
+ init_completion(&kthread->exited);
+ init_completion(&kthread->parked);
+ p->vfork_done = &kthread->exited;
+
/*
* We abuse ->set_child_tid to avoid the new member and because it
- * can't be wrongly copied by copy_process(). We also rely on fact
- * that the caller can't exec, so PF_KTHREAD can't be cleared.
+ * can't be wrongly copied by copy_process().
*/
p->set_child_tid = (__force void __user *)kthread;
+ return true;
}
void free_kthread_struct(struct task_struct *k)
@@ -114,13 +121,13 @@ void free_kthread_struct(struct task_struct *k)
struct kthread *kthread;
/*
- * Can be NULL if this kthread was created by kernel_thread()
- * or if kmalloc() in kthread() failed.
+ * Can be NULL if kmalloc() in set_kthread_struct() failed.
*/
kthread = to_kthread(k);
#ifdef CONFIG_BLK_CGROUP
WARN_ON_ONCE(kthread && kthread->blkcg_css);
#endif
+ k->set_child_tid = (__force void __user *)NULL;
kfree(kthread);
}
@@ -315,7 +322,6 @@ static int kthread(void *_create)
struct kthread *self;
int ret;
- set_kthread_struct(current);
self = to_kthread(current);
/* If user was SIGKILLed, I release the structure. */
@@ -325,17 +331,8 @@ static int kthread(void *_create)
kthread_exit(-EINTR);
}
- if (!self) {
- create->result = ERR_PTR(-ENOMEM);
- complete(done);
- kthread_exit(-ENOMEM);
- }
-
self->threadfn = threadfn;
self->data = data;
- init_completion(&self->exited);
- init_completion(&self->parked);
- current->vfork_done = &self->exited;
/*
* The new thread inherited kthreadd's priority and CPU mask. Reset