linux-kernel - [PATCH 4/4] iommu/vt-d: Fix PCI device refcount leak in dmar_dev_scope

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Date:   Thu,  1 Dec 2022 12:01:27 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>
Cc:     Xiongfeng Wang <wangxiongfeng2@...wei.com>,
        Yang Yingliang <yangyingliang@...wei.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH 4/4] iommu/vt-d: Fix PCI device refcount leak in dmar_dev_scope_init()

From: Xiongfeng Wang <wangxiongfeng2@...wei.com>

for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.

If we break for_each_pci_dev() loop with pdev not NULL, we need to call
pci_dev_put() to decrease the reference count. Add the missing
pci_dev_put() for the error path to avoid reference count leak.

Fixes: 2e4552893038 ("iommu/vt-d: Unify the way to process DMAR device scope array")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@...wei.com>
Link: https://lore.kernel.org/r/20221121113649.190393-3-wangxiongfeng2@huawei.com
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/intel/dmar.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 5a8f780e7ffd..bc94059a5b87 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -820,6 +820,7 @@ int __init dmar_dev_scope_init(void)
 			info = dmar_alloc_pci_notify_info(dev,
 					BUS_NOTIFY_ADD_DEVICE);
 			if (!info) {
+				pci_dev_put(dev);
 				return dmar_dev_scope_status;
 			} else {
 				dmar_pci_bus_add_dev(info);
-- 
2.34.1