Commit f74c371f authored Oct 04, 2018 by Eric Dumazet Committed by Dmitry Torokhov Oct 04, 2018

Input: mousedev - add a schedule point in mousedev_write()

syzbot was able to trigger rcu stalls by calling write()
with large number of bytes.

Add a cond_resched() in the loop to avoid this.

Link: https://lkml.org/lkml/2018/8/23/1106


Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by:  <syzbot+9436b02171ac0894d33e@syzkaller.appspotmail.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

parent 684bec10

drivers/input/mousedev.c

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -707,6 +707,7 @@ static ssize_t mousedev_write(struct file file, const char __user buffer,
	mousedev_generate_response(client, c);		mousedev_generate_response(client, c);

	spin_unlock_irq(&client->packet_lock);		spin_unlock_irq(&client->packet_lock);
			cond_resched();
	}		}

	kill_fasync(&client->fasync, SIGIO, POLL_IN);		kill_fasync(&client->fasync, SIGIO, POLL_IN);