---

yaml
---
r: 295475
b: refs/heads/master
c: 4e474a0
h: refs/heads/master
i:
  295473: 64df37a
  295471: 8c8cca9
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4e75732035d7e97e001bdf6e3149d3967c0221de
+refs/heads/master: 4e474a00d7ff746ed177ddae14fa8b2d4bad7a00

trunk/fs/proc/proc_sysctl.c

@@ -525,27 +525,40 @@ static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
 
 static int proc_sys_open(struct inode *inode, struct file *filp)
 {
+	struct ctl_table_header *head = grab_header(inode);
 	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
 
+	/* sysctl was unregistered */
+	if (IS_ERR(head))
+		return PTR_ERR(head);
+
 	if (table->poll)
 		filp->private_data = proc_sys_poll_event(table->poll);
 
+	sysctl_head_finish(head);
+
 	return 0;
 }
 
 static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
 {
 	struct inode *inode = filp->f_path.dentry->d_inode;
+	struct ctl_table_header *head = grab_header(inode);
 	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
-	unsigned long event = (unsigned long)filp->private_data;
 	unsigned int ret = DEFAULT_POLLMASK;
+	unsigned long event;
+
+	/* sysctl was unregistered */
+	if (IS_ERR(head))
+		return POLLERR | POLLHUP;
 
 	if (!table->proc_handler)
 		goto out;
 
 	if (!table->poll)
 		goto out;
 
+	event = (unsigned long)filp->private_data;
 	poll_wait(filp, &table->poll->wait, wait);
 
 	if (event != atomic_read(&table->poll->event)) {
@@ -554,6 +567,8 @@ static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
 	}
 
 out:
+	sysctl_head_finish(head);
+
 	return ret;
 }