On 04/11/2025 01:28, Ma Ke wrote:
If device_add() fails, do not use device_unregister() for error handling. device_unregister() consists two functions: device_del() and put_device(). device_unregister() should only be called after device_add() succeeded because device_del() undoes what device_add() does if successful.
As comment of device_add() says, 'if device_add() succeeds, you should call device_del() when you want to get rid of it. If device_add() has not succeeded, use only put_device() to drop the reference count'.
In tegra_xusb_pad_init(), both dev_set_name() and device_add() may fail. In either case, we should only use put_device(). After device_initialize(), the device has a reference count of 1. If dev_set_name() fails, device_add() has not been called. If device_add() fails, it has already cleaned up after itself. device_unregister() would incorrectly call device_del() when device_add() was never successful. Therefore, change both error paths to use put_device() instead of device_unregister().
Ideally, we would make all of the above a bit more concise/simple. However, this does look correct to me ...
Found by code review.
Cc: stable@vger.kernel.org Fixes: 53d2a715c240 ("phy: Add Tegra XUSB pad controller support") Signed-off-by: Ma Ke make24@iscas.ac.cn
Changes in v2:
- modified the Fixes tag;
- modified the patch description.
drivers/phy/tegra/xusb.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c index c89df95aa6ca..d89493d68699 100644 --- a/drivers/phy/tegra/xusb.c +++ b/drivers/phy/tegra/xusb.c @@ -171,16 +171,16 @@ int tegra_xusb_pad_init(struct tegra_xusb_pad *pad, err = dev_set_name(&pad->dev, "%s", pad->soc->name); if (err < 0)
goto unregister;
goto put_device;err = device_add(&pad->dev); if (err < 0)
goto unregister;
goto put_device;return 0; -unregister:
- device_unregister(&pad->dev);
+put_device:
- put_device(&pad->dev); return err; }
Reviewed-by: Jon Hunter jonathanh@nvidia.com
Thanks Jon