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From:   Xiongfeng Wang <wangxiongfeng2@huawei.com>
To:     <olivia@selenic.com>, <herbert@gondor.apana.org.au>,
        <mpm@selenic.com>, <mb@bu3sch.de>, <dilinger@queued.net>
CC:     <linux-crypto@vger.kernel.org>, <yangyingliang@huawei.com>,
        <wangxiongfeng2@huawei.com>
Subject: [PATCH v2 2/2] hwrng: geode - Fix PCI device refcount leak
Date:   Fri, 2 Dec 2022 21:22:34 +0800
Message-ID: <20221202132234.60631-3-wangxiongfeng2@huawei.com>
In-Reply-To: <20221202132234.60631-1-wangxiongfeng2@huawei.com>
References: <20221202132234.60631-1-wangxiongfeng2@huawei.com>
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Precedence: bulk

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. We add a new struct
'amd_geode_priv' to record pointer of the pci_dev and membase, and then
add missing pci_dev_put() for the normal and error path.

Fixes: ef5d862734b8 ("[PATCH] Add Geode HW RNG driver")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
---
 drivers/char/hw_random/geode-rng.c | 36 +++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/char/hw_random/geode-rng.c b/drivers/char/hw_random/geode-rng.c
index 138ce434f86b..12fbe8091831 100644
--- a/drivers/char/hw_random/geode-rng.c
+++ b/drivers/char/hw_random/geode-rng.c
@@ -51,6 +51,10 @@ static const struct pci_device_id pci_tbl[] = {
 };
 MODULE_DEVICE_TABLE(pci, pci_tbl);
 
+struct amd_geode_priv {
+	struct pci_dev *pcidev;
+	void __iomem *membase;
+};
 
 static int geode_rng_data_read(struct hwrng *rng, u32 *data)
 {
@@ -90,6 +94,7 @@ static int __init geode_rng_init(void)
 	const struct pci_device_id *ent;
 	void __iomem *mem;
 	unsigned long rng_base;
+	struct amd_geode_priv *priv;
 
 	for_each_pci_dev(pdev) {
 		ent = pci_match_id(pci_tbl, pdev);
@@ -97,17 +102,26 @@ static int __init geode_rng_init(void)
 			goto found;
 	}
 	/* Device not found. */
-	goto out;
+	return err;
 
 found:
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		err = -ENOMEM;
+		goto put_dev;
+	}
+
 	rng_base = pci_resource_start(pdev, 0);
 	if (rng_base == 0)
-		goto out;
+		goto free_priv;
 	err = -ENOMEM;
 	mem = ioremap(rng_base, 0x58);
 	if (!mem)
-		goto out;
-	geode_rng.priv = (unsigned long)mem;
+		goto free_priv;
+
+	geode_rng.priv = (unsigned long)priv;
+	priv->membase = mem;
+	priv->pcidev = pdev;
 
 	pr_info("AMD Geode RNG detected\n");
 	err = hwrng_register(&geode_rng);
@@ -116,20 +130,26 @@ static int __init geode_rng_init(void)
 		       err);
 		goto err_unmap;
 	}
-out:
 	return err;
 
 err_unmap:
 	iounmap(mem);
-	goto out;
+free_priv:
+	kfree(priv);
+put_dev:
+	pci_dev_put(pdev);
+	return err;
 }
 
 static void __exit geode_rng_exit(void)
 {
-	void __iomem *mem = (void __iomem *)geode_rng.priv;
+	struct amd_geode_priv *priv;
 
+	priv = (struct amd_geode_priv *)geode_rng.priv;
 	hwrng_unregister(&geode_rng);
-	iounmap(mem);
+	iounmap(priv->membase);
+	pci_dev_put(priv->pcidev);
+	kfree(priv);
 }
 
 module_init(geode_rng_init);
-- 
2.20.1