[PATCH] kvm: ensure that debugfs entries have been created

[Hamo]

by checking the return value from kvm_init_debug, we
can ensure that the entries under debugfs for KVM have
been created correctly.

Signed-off-by: Yang Bai <hamo.by@xxxxxxxxx>
---
 virt/kvm/kvm_main.c |   26 +++++++++++++++++++++++---
 1 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d9cfb78..a338273 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2612,15 +2612,29 @@ static const struct file_operations *stat_fops[] = {
 	[KVM_STAT_VM]   = &vm_stat_fops,
 };

-static void kvm_init_debug(void)
+static int kvm_init_debug(void)
 {
+	int r = -EFAULT;
 	struct kvm_stats_debugfs_item *p;

 	kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
-	for (p = debugfs_entries; p->name; ++p)
+	if (kvm_debugfs_dir == NULL)
+		goto out;
+
+	for (p = debugfs_entries; p->name; ++p) {
 		p->dentry = debugfs_create_file(p->name, 0444, kvm_debugfs_dir,
 						(void *)(long)p->offset,
 						stat_fops[p->kind]);
+		if (p->dentry == NULL)
+			goto out_dir;
+	}
+
+	return 0;
+
+out_dir:
+	debugfs_remove_recursive(kvm_debugfs_dir);
+out:
+	return r;
 }

 static void kvm_exit_debug(void)
@@ -2764,10 +2778,16 @@ int kvm_init(void *opaque, unsigned vcpu_size,
unsigned vcpu_align,
 	kvm_preempt_ops.sched_in = kvm_sched_in;
 	kvm_preempt_ops.sched_out = kvm_sched_out;

-	kvm_init_debug();
+	r = kvm_init_debug();
+	if (r) {
+		printk(KERN_ERR "kvm: create debugfs files failed\n");
+		goto out_undebugfs;
+	}

 	return 0;

+out_undebugfs:
+	unregister_syscore_ops(&kvm_syscore_ops);
 out_unreg:
 	kvm_async_pf_deinit();
 out_free:
-- 
1.7.1
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