Once device_add() failed, we should call put_device() to decrement reference count for cleanup. Or it could cause memory leak.
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'.
Found by code review.
Cc: stable@vger.kernel.org Fixes: 8ed633b9baf9 ("Revert "net-sysfs: Fix memory leak in netdev_register_kobject"") Signed-off-by: Ma Ke make24@iscas.ac.cn --- net/core/net-sysfs.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 07cb99b114bd..f443eacc9237 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -2169,6 +2169,7 @@ int netdev_register_kobject(struct net_device *ndev)
error = device_add(dev); if (error) + put_device(dev); return error;
error = register_queue_kobjects(ndev);
On Thu, Mar 13, 2025 at 03:55:28PM +0800, Ma Ke wrote:
Once device_add() failed, we should call put_device() to decrement reference count for cleanup. Or it could cause memory leak.
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'.
Okay, have you read the history of this? 6b70fc94afd1 ("net-sysfs: Fix memory leak in netdev_register_kobject") 8ed633b9baf9 ("Revert "net-sysfs: Fix memory leak in netdev_register_kobject"") https://syzkaller.appspot.com/x/log.txt?x=1737671b200000
TL;DR: next time provide a better changelog and clean syzkaller report.
+Cc: Wang Hai
On Thu, Mar 13, 2025 at 11:01:18AM +0200, Andy Shevchenko wrote:
On Thu, Mar 13, 2025 at 03:55:28PM +0800, Ma Ke wrote:
Once device_add() failed, we should call put_device() to decrement reference count for cleanup. Or it could cause memory leak.
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'.
Okay, have you read the history of this? 6b70fc94afd1 ("net-sysfs: Fix memory leak in netdev_register_kobject") 8ed633b9baf9 ("Revert "net-sysfs: Fix memory leak in netdev_register_kobject"") https://syzkaller.appspot.com/x/log.txt?x=1737671b200000
TL;DR: next time provide a better changelog and clean syzkaller report.
On Thu, Mar 13, 2025 at 03:55:28PM +0800, Ma Ke wrote:
Once device_add() failed, we should call put_device() to decrement reference count for cleanup. Or it could cause memory leak.
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'.
Found by code review.
Cc: stable@vger.kernel.org Fixes: 8ed633b9baf9 ("Revert "net-sysfs: Fix memory leak in netdev_register_kobject"") Signed-off-by: Ma Ke make24@iscas.ac.cn
net/core/net-sysfs.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 07cb99b114bd..f443eacc9237 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -2169,6 +2169,7 @@ int netdev_register_kobject(struct net_device *ndev) error = device_add(dev); if (error)
put_device(dev);
You obviously did not test this :(
Please be more careful in the future.
linux-stable-mirror@lists.linaro.org
-
Andy Shevchenko -
Greg KH -
Ma Ke