[3.11.y.z extended stable] Patch "kvm: free resources after canceling async_pf" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    kvm: free resources after canceling async_pf

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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>From 112c5d4f946e09c7ba0fab75cab19eaa2ab5056d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar at redhat.com>
Date: Wed, 4 Sep 2013 22:32:23 +0200
Subject: kvm: free resources after canceling async_pf
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Content-Type: text/plain; charset=UTF-8
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commit 28b441e24088081c1e213139d1303b451a34a4f4 upstream.

When we cancel 'async_pf_execute()', we should behave as if the work was
never scheduled in 'kvm_setup_async_pf()'.
Fixes a bug when we can't unload module because the vm wasn't destroyed.

Signed-off-by: Radim Krčmář <rkrcmar at redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini at redhat.com>
Reviewed-by: Gleb Natapov <gleb at redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 virt/kvm/async_pf.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index ea475cd03511..8a39dda7a325 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -101,8 +101,11 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 				   typeof(*work), queue);
 		cancel_work_sync(&work->work);
 		list_del(&work->queue);
-		if (!work->done) /* work was canceled */
+		if (!work->done) { /* work was canceled */
+			mmdrop(work->mm);
+			kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
 			kmem_cache_free(async_pf_cache, work);
+		}
 	}

 	spin_lock(&vcpu->async_pf.lock);
--
1.9.1