Re: [PATCH] net: llc: add lock_sock in llc_ui_bind to avoid a race condition

[David Miller]

From: Lin Zhang <xiaolou4617@xxxxxxxxx>
Date: Thu, 25 May 2017 14:07:18 +0800

> There is a race condition in llc_ui_bind if two or more processes/threads 
> try to bind a same socket.
> 
> If more processes/threads bind a same socket success that will lead to 
> two problems, one is this action is not what we expected, another is 
> will lead to kernel in unstable status or oops(in my simple test case, 
> cause llc2.ko can't unload).
> 
> The current code is test SOCK_ZAPPED bit to avoid a process to 
> bind a same socket twice but that is can't avoid more processes/threads 
> try to bind a same socket at the same time.
> 
> So, add lock_sock in llc_ui_bind like others, such as llc_ui_connect.
> 
> Signed-off-by: Lin Zhang <xiaolou4617@xxxxxxxxx>

Applied, thank you.