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From: Will Deacon <will.deacon@arm.com>
To: Balbir Singh <bsingharora@gmail.com>
Cc: kvm@vger.kernel.org, mpe@ellerman.id.au, mikey@neuling.org
Subject: Re: [PATCH 4/5] Fix a race during exit processing
Date: Mon, 11 Apr 2016 16:37:29 +0100	[thread overview]
Message-ID: <20160411153728.GB19749@arm.com> (raw)
In-Reply-To: <1459423707-8956-5-git-send-email-bsingharora@gmail.com>

On Thu, Mar 31, 2016 at 10:28:26PM +1100, Balbir Singh wrote:
> Fix a race, described below
> 
> 	lkvm stop ...	handle_stop
> 			kvm_cpu__reboot
> 			kvm_cmd_run_exit
> 			vcpus exit
> 			...
> 			dev_exit
> 			...
> 			ioport__unregister
> 			..serial...
> 			kvm__pause --> br_write_lock
> 			pthread_kill
> 
> But the thread is already dead above.
> 
> We mark the cpus as dying so that kvm_pause does nothing.
> This should not break any semantics

I'm not convinced that this solves the whole problem. The fact of the
matter is that we're tearing down the VM whilst there may still be active
vcpus, so I'd much rather delay the teardown until we know that the vcpus
are all dead.

Patch incoming.

Will

  reply	other threads:[~2016-04-11 15:37 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-31 11:28 [PATCH 0/5] Add support for ppc64le in kvmtool Balbir Singh
2016-03-31 11:28 ` [PATCH 1/5] Add basic little endian support Balbir Singh
2016-03-31 11:28 ` [PATCH 2/5] Add basic infrastructure to run tasks on vCPUs Balbir Singh
2016-04-01 10:42   ` Michael Ellerman
2016-04-01 11:29     ` Balbir Singh
2016-04-01 12:27       ` Will Deacon
2016-04-07  1:12         ` Balbir Singh
2016-03-31 11:28 ` [PATCH 3/5] Implement H_SET_MODE for ppc64le Balbir Singh
2016-03-31 11:28 ` [PATCH 4/5] Fix a race during exit processing Balbir Singh
2016-04-11 15:37   ` Will Deacon [this message]
2016-03-31 11:28 ` [PATCH 5/5] Implement spapr pci for little endian systems Balbir Singh
2016-03-31 13:38 ` [PATCH 0/5] Add support for ppc64le in kvmtool Laurent Vivier
2016-04-01  0:12   ` Balbir Singh
2016-04-04  8:34     ` Balbir Singh
2016-04-04  8:41       ` Laurent Vivier
2016-04-04 10:24         ` Balbir Singh
2016-04-04 12:21           ` Laurent Vivier
2016-04-01 10:47 ` Michael Ellerman
2016-04-01 10:48   ` Will Deacon

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