[patch] kvm: fix GFP_KERNEL allocation in atomic section in kvm_dev_ioctl_create_vcpu()

[Ingo Molnar <mingo@elte.hu>]

Subject: [patch] kvm: fix GFP_KERNEL allocation in atomic section in kvm_dev_ioctl_create_vcpu()
From: Ingo Molnar <mingo@elte.hu>

fix a GFP_KERNEL allocation in atomic section bug: 
kvm_dev_ioctl_create_vcpu() called kvm_mmu_init(), which calls 
alloc_pages(), while holding the vcpu. The fix is to set up the MMU 
state earlier, it does not require a loaded CPU state.

(NOTE: free_vcpus does an kvm_mmu_destroy() call so there's no need
 for any extra teardown branch on allocation failure here.)

found in 2.6.20-rc2-rt1.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 drivers/kvm/kvm_main.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Index: linux/drivers/kvm/kvm_main.c
===================================================================
--- linux.orig/drivers/kvm/kvm_main.c
+++ linux/drivers/kvm/kvm_main.c
@@ -522,12 +522,12 @@ static int kvm_dev_ioctl_create_vcpu(str
 	if (r < 0)
 		goto out_free_vcpus;
 
-	kvm_arch_ops->vcpu_load(vcpu);
+	r = kvm_mmu_init(vcpu);
+	if (r < 0)
+		goto out_free_vcpus;
 
+	kvm_arch_ops->vcpu_load(vcpu);
 	r = kvm_arch_ops->vcpu_setup(vcpu);
-	if (r >= 0)
-		r = kvm_mmu_init(vcpu);
-
 	vcpu_put(vcpu);
 
 	if (r < 0)