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From: Oleg Nesterov <oleg@redhat.com>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Rusty Russell <rusty@rustcorp.com.au>, Tejun Heo <tj@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: + kmod-avoid-deadlock-by-recursive-kmod-call.patch added to -mm tree
Date: Thu, 26 Jan 2012 18:56:12 +0100	[thread overview]
Message-ID: <20120126175612.GA24011@redhat.com> (raw)

> @@ -449,6 +460,16 @@ int call_usermodehelper_exec(struct subp
>  		retval = -EBUSY;
>  		goto out;
>  	}
> +	/*
> +	 * Worker thread must not wait for khelper thread at below
> +	 * wait_for_completion() if the thread was created with CLONE_VFORK
> +	 * flag, for khelper thread is already waiting for the thread at
> +	 * wait_for_completion() in do_fork().
> +	 */
> +	if (wait != UMH_NO_WAIT && current == kmod_thread_locker) {
> +		retval = -EBUSY;
> +		goto out;
> +	}

So, this is because khelper_wq's max_active == 1.

Can't we simply kill khelper_wq and use system_unbound_wq instead?

Oleg.


             reply	other threads:[~2012-01-26 19:16 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-26 17:56 Oleg Nesterov [this message]
2012-01-27  2:55 ` + kmod-avoid-deadlock-by-recursive-kmod-call.patch added to -mm tree Rusty Russell
2012-01-27 14:32   ` Oleg Nesterov
2012-01-29  0:49     ` Rusty Russell
2012-01-29 16:31       ` Oleg Nesterov
2012-01-29 23:26         ` Rusty Russell
2012-01-30  0:25           ` Tejun Heo
2012-01-30 13:03             ` Oleg Nesterov
2012-01-30 17:28               ` Tejun Heo
2012-02-03 18:00                 ` Oleg Nesterov
2012-02-03 19:26                   ` Tejun Heo
2012-02-04 12:56                   ` + kmod-avoid-deadlock-by-recursive-kmod-call.patch added to-mm tree Tetsuo Handa
2012-02-06 17:19                     ` Oleg Nesterov
2012-01-30 12:38           ` + kmod-avoid-deadlock-by-recursive-kmod-call.patch added to -mm tree Oleg Nesterov

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