Re: + syscalls-x86-add-__nr_kcmp-syscall-v8.patch added to -mm tree

[Vasiliy Kulikov]

On Thu, Feb 16, 2012 at 20:49 +0400, Cyrill Gorcunov wrote:
> +	err = mutex_lock_killable(m1);
> +	if (!err && likely(m1 != m2)) {
> +		err = mutex_lock_killable_nested(m2, SINGLE_DEPTH_NESTING);

Doesn't it lead to a deadlock?

mutex_lock_killable(task1)
|					mutex_lock_killable(task2)
mutex_lock_killable_nested(task2)	|
(locked)				|
					mutex_lock_killable_nested(task1)
					(locked)

I suppose you should use some global lock (kcmp_lock) before both locks.

Thanks,

-- 
Vasiliy Kulikov
http://www.openwall.com - bringing security into open computing environments
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