[PATCH 6.0 0657/1073] hwrng: amd - Fix PCI device refcount leak

Greg Kroah-Hartman
2022-12-28T16:15:38Z

From: Xiongfeng Wang <wangxiongfeng2@huawei.com>

[ Upstream commit ecadb5b0111ea19fc7c240bb25d424a94471eb7d ]

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 normal and error path.

Fixes: 96d63c0297cc ("[PATCH] Add AMD HW RNG driver")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/char/hw_random/amd-rng.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
index c22d4184bb61..0555e3838bce 100644
--- a/drivers/char/hw_random/amd-rng.c
+++ b/drivers/char/hw_random/amd-rng.c
@@ -143,15 +143,19 @@ static int __init amd_rng_mod_init(void)
found:
err = pci_read_config_dword(pdev, 0x58, &pmbase);
if (err)
- return err;
+ goto put_dev;

pmbase &= 0x0000FF00;
- if (pmbase == 0)
- return -EIO;
+ if (pmbase == 0) {
+ err = -EIO;
+ goto put_dev;
+ }

priv = kzalloc(sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
+ if (!priv) {
+ err = -ENOMEM;
+ goto put_dev;
+ }

if (!request_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE, DRV_NAME)) {
dev_err(&pdev->dev, DRV_NAME " region 0x%x already in use!\n",
@@ -185,6 +189,8 @@ static int __init amd_rng_mod_init(void)
release_region(pmbase + PMBASE_OFFSET, PMBASE_SIZE);
out:
kfree(priv);
+put_dev:
+ pci_dev_put(pdev);
return err;
}

@@ -200,6 +206,8 @@ static void __exit amd_rng_mod_exit(void)

release_region(priv->pmbase + PMBASE_OFFSET, PMBASE_SIZE);

+ pci_dev_put(priv->pcidev);
+
kfree(priv);
}

--
2.35.1