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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	xen-devel@lists.xenproject.org
Cc: Ross Lagerwall <ross.lagerwall@citrix.com>,
	Julien Grall <julien.grall@arm.com>,
	Jan Beulich <jbeulich@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH for v4.9] livepatch: Wrong usage of spinlock on debug console.
Date: Fri, 9 Jun 2017 13:12:10 -0400	[thread overview]
Message-ID: <2fb01e48-9a1f-170f-c635-43a07d2c6029@oracle.com> (raw)
In-Reply-To: <20170609141639.8903-1-konrad.wilk@oracle.com>

On 06/09/2017 10:16 AM, Konrad Rzeszutek Wilk wrote:
> If we have a large amount of livepatches and want to print them
> on the console using 'xl debug-keys x' we eventually hit
> the preemption check:
>
>   if ( i && !(i % 64) )
>   {
> 	spin_unlock(&payload_lock);
> 	process_pending_softirqs();
> 	if ( spin_trylock(&payload_lock) )
> 		return
>
> <facepalm> The effect is that we have just effectively
> taken the lock and returned without unlocking!
>
> CC: Ross Lagerwall <ross.lagerwall@citrix.com>
> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> CC: Jan Beulich <jbeulich@suse.com>
> CC: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Julien Grall <julien.grall@arm.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>


Reviewed-and-tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>



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  parent reply	other threads:[~2017-06-09 17:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-09 14:16 [PATCH for v4.9] livepatch: Wrong usage of spinlock on debug console Konrad Rzeszutek Wilk
2017-06-09 14:53 ` Jan Beulich
2017-06-09 15:05 ` Ross Lagerwall
2017-06-09 17:12 ` Boris Ostrovsky [this message]
2017-06-11 12:15   ` Is: Release-ack for 4.9, Is:Re: " Konrad Rzeszutek Wilk
2017-06-12 11:08     ` Julien Grall

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