[PATCH 3/3] Revert "KVM: Prevent module exit until all VMs are freed"

[Sean Christopherson]

Revert KVM's misguided attempt to "fix" a use-after-module-unload bug that
was actually due to failure to flush a workqueue, not a lack of module
refcounting.

blah blah blah

This reverts commit 405294f29faee5de8c10cb9d4a90e229c2835279 and commit
commit 5f6de5cbebee925a612856fce6f9182bb3eee0db.

Fixes: 405294f29fae ("KVM: Unconditionally get a ref to /dev/kvm module when creating a VM")
Fixes: 5f6de5cbebee ("KVM: Prevent module exit until all VMs are freed")
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 virt/kvm/kvm_main.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1e65a506985f..3b1b9e8dd70c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -115,8 +115,6 @@ EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
 
 static const struct file_operations stat_fops_per_vm;
 
-static struct file_operations kvm_chardev_ops;
-
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
 			   unsigned long arg);
 #ifdef CONFIG_KVM_COMPAT
@@ -1157,9 +1155,6 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
 	if (!kvm)
 		return ERR_PTR(-ENOMEM);
 
-	/* KVM is pinned via open("/dev/kvm"), the fd passed to this ioctl(). */
-	__module_get(kvm_chardev_ops.owner);
-
 	KVM_MMU_LOCK_INIT(kvm);
 	mmgrab(current->mm);
 	kvm->mm = current->mm;
@@ -1279,7 +1274,6 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
 out_err_no_srcu:
 	kvm_arch_free_vm(kvm);
 	mmdrop(current->mm);
-	module_put(kvm_chardev_ops.owner);
 	return ERR_PTR(r);
 }
 
@@ -1348,7 +1342,6 @@ static void kvm_destroy_vm(struct kvm *kvm)
 	preempt_notifier_dec();
 	hardware_disable_all();
 	mmdrop(mm);
-	module_put(kvm_chardev_ops.owner);
 }
 
 void kvm_get_kvm(struct kvm *kvm)
-- 
2.42.0.609.gbb76f46606-goog


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