linux-kernel - [PATCH 3/3] VMCI: Fix some error handling paths in vmci_guest_probe

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Date:   Thu, 10 Feb 2022 23:27:34 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     jhansen@...are.com, vdasa@...are.com, arnd@...db.de,
        gregkh@...uxfoundation.org, acking@...are.com, dtor@...are.com
Cc:     pv-drivers@...are.com, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH 3/3] VMCI: Fix some error handling paths in vmci_guest_probe_device()

The 'err_remove_vmci_dev_g' error label is not at the right place.
This could lead to un-released resource.

There is also a missing label. If pci_alloc_irq_vectors() fails, the
previous vmci_event_subscribe() call must be undone.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
Review with GREAT care.

This patch is a recent rebase of an old patch that has never been
submitted.
This function is huge and modifying its error handling path is error
prone (at least for me).

The patch is compile-tested only.
---
 drivers/misc/vmw_vmci/vmci_guest.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c
index 02d4722d8474..2e8ad36895ae 100644
--- a/drivers/misc/vmw_vmci/vmci_guest.c
+++ b/drivers/misc/vmw_vmci/vmci_guest.c
@@ -765,7 +765,7 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
 	/* Check host capabilities. */
 	error = vmci_check_host_caps(pdev);
 	if (error)
-		goto err_remove_bitmap;
+		goto err_remove_vmci_dev_g;
 
 	/* Enable device. */
 
@@ -795,7 +795,7 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
 		error = pci_alloc_irq_vectors(pdev, 1, 1,
 				PCI_IRQ_MSIX | PCI_IRQ_MSI | PCI_IRQ_LEGACY);
 		if (error < 0)
-			goto err_remove_bitmap;
+			goto err_unsubscrive_event;
 	} else {
 		vmci_dev->exclusive_vectors = true;
 	}
@@ -871,13 +871,19 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
 err_disable_msi:
 	pci_free_irq_vectors(pdev);
 
+err_unsubscrive_event:
 	vmci_err = vmci_event_unsubscribe(ctx_update_sub_id);
 	if (vmci_err < VMCI_SUCCESS)
 		dev_warn(&pdev->dev,
 			 "Failed to unsubscribe from event (type=%d) with subscriber (ID=0x%x): %d\n",
 			 VMCI_EVENT_CTX_ID_UPDATE, ctx_update_sub_id, vmci_err);
 
-err_remove_bitmap:
+err_remove_vmci_dev_g:
+	spin_lock_irq(&vmci_dev_spinlock);
+	vmci_pdev = NULL;
+	vmci_dev_g = NULL;
+	spin_unlock_irq(&vmci_dev_spinlock);
+
 	if (vmci_dev->notification_bitmap) {
 		vmci_write_reg(vmci_dev, VMCI_CONTROL_RESET, VMCI_CONTROL_ADDR);
 		dma_free_coherent(&pdev->dev, PAGE_SIZE,
@@ -885,12 +891,6 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
 				  vmci_dev->notification_base);
 	}
 
-err_remove_vmci_dev_g:
-	spin_lock_irq(&vmci_dev_spinlock);
-	vmci_pdev = NULL;
-	vmci_dev_g = NULL;
-	spin_unlock_irq(&vmci_dev_spinlock);
-
 err_free_data_buffers:
 	vmci_free_dg_buffers(vmci_dev);
 
-- 
2.32.0