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From: Rusty Russell <rusty@rustcorp.com.au>
To: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Andrew Morton <akpm@osdl.org>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] call_usermodehelper needs to wait longer
Date: Wed, 10 Mar 2004 21:47:43 +1100	[thread overview]
Message-ID: <1078915663.23776.4.camel@bach> (raw)
In-Reply-To: <20040310082416.GA5084@in.ibm.com>

On Wed, 2004-03-10 at 19:24, Srivatsa Vaddagiri wrote:
> On Tue, Mar 09, 2004 at 01:38:35PM -0800, Andrew Morton wrote:
> > I'm not so sure about this.  There are deadlock potentials if the usermode
> > application wants to perform some function which requires keventd services
> > to complete - the application cannot complete because keventd is itself
> > waiting for the application.
> > 
> > Can we think of any circumstances under which keventd _should_
> > synchronously wait for the userspace app?
> 
> Honestly I don't know ..Would it be reasonable for somebody
> to call request_module from a work function (in which case the above
> bug is exposed)? I agree it is not a nice thing if we block keventd
> waiting for the app to exit. 

I think a BUG_ON(wait) is arguably right here: anyone trying it will hit
it immediately.  Perhaps a "/* keventd shouldn't block */" comment above
it would help.

Cheers,
-- 
Anyone who quotes me in their signature is an idiot -- Rusty Russell


      reply	other threads:[~2004-03-10 10:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-03-09 13:51 [PATCH] call_usermodehelper needs to wait longer Srivatsa Vaddagiri
2004-03-09 21:38 ` Andrew Morton
2004-03-10  8:24   ` Srivatsa Vaddagiri
2004-03-10 10:47     ` Rusty Russell [this message]

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