On Fri, Nov 7, 2025 at 12:01 AM Ma Ke make24@iscas.ac.cn wrote:
After calling device_initialize(), the reference count of the device is set to 1. If device_add() fails or register_queue_kobjects() fails, the function returns without calling put_device() to release the initial reference, causing a memory leak of the device structure. Similarly, in netdev_unregister_kobject(), after calling device_del(), there is no call to put_device() to release the initial reference, leading to a memory leak. Add put_device() in the error paths of netdev_register_kobject() and after device_del() in netdev_unregister_kobject() to properly release the device references.
Found by code review.
Cc: stable@vger.kernel.org Fixes: a1b3f594dc5f ("net: Expose all network devices in a namespaces in sysfs") Signed-off-by: Ma Ke make24@iscas.ac.cn
net/core/net-sysfs.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index ca878525ad7c..d3895f26a0c8 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -2327,6 +2327,7 @@ void netdev_unregister_kobject(struct net_device *ndev) pm_runtime_set_memalloc_noio(dev, false);
device_del(dev);
put_device(dev);
Please take a look at free_netdev()
}
/* Create sysfs entries for network device. */ @@ -2357,7 +2358,7 @@ int netdev_register_kobject(struct net_device *ndev)
error = device_add(dev); if (error)
return error;
goto out_put_device; error = register_queue_kobjects(ndev); if (error) {@@ -2367,6 +2368,10 @@ int netdev_register_kobject(struct net_device *ndev)
pm_runtime_set_memalloc_noio(dev, true);
return 0;+out_put_device:
put_device(dev); return error;
This seems bogus.
Was your report based on AI or some tooling ?
You would think that syzbot would have found an issue a long time ago...