Re: [syzbot] Re: [syzbot] [kernel?] KMSAN: kernel-infoleak in vmci_host_unlocked_ioctl (3)

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Subject: Re: [syzbot] [kernel?] KMSAN: kernel-infoleak in vmci_host_unlocked_ioctl (3)
Author: lizhi.xu@windriver.com

#syz test

diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c
index b64944367ac5..8bca943b9f4b 100644
--- a/drivers/misc/vmw_vmci/vmci_host.c
+++ b/drivers/misc/vmw_vmci/vmci_host.c
@@ -91,7 +91,7 @@ struct vmci_host_dev {
 static struct vmci_ctx *host_context;
 static bool vmci_host_device_initialized;
 static atomic_t vmci_host_active_users = ATOMIC_INIT(0);
-
+static atomic_t vmci_host_dev_open = ATOMIC_INIT(0);
 /*
  * Determines whether the VMCI host personality is
  * available. Since the core functionality of the host driver is
@@ -120,6 +120,11 @@ static int vmci_host_open(struct inode *inode, struct file *filp)
 {
 	struct vmci_host_dev *vmci_host_dev;
 
+	if (atomic_inc_return(&vmci_host_dev_open) > 1) {
+		atomic_dec(&vmci_host_dev_open);
+		return -EBUSY;
+	}
+
 	vmci_host_dev = kzalloc(sizeof(struct vmci_host_dev), GFP_KERNEL);
 	if (vmci_host_dev == NULL)
 		return -ENOMEM;