UBUNTU-CVE-2025-21701
In the Linux kernel, the following vulnerability has been resolved: net: avoid race between device unregistration and ethnl ops The following trace can be seen if a device is being unregistered while its number of channels are being modified. DEBUG_LOCKS_WARN_ON(lock->magic != lock) WARNING: CPU: 3 PID: 3754 at kernel/locking/mutex.c:564 __mutex_lock+0xc8a/0x1120 CPU: 3 UID: 0 PID: 3754 Comm: ethtool Not tainted 6.13.0-rc6+ #771 RIP: 0010:__mutex_lock+0xc8a/0x1120 Call Trace: <TASK> ethtool_check_max_channel+0x1ea/0x880 ethnl_set_channels+0x3c3/0xb10 ethnl_default_set_doit+0x306/0x650 genl_family_rcv_msg_doit+0x1e3/0x2c0 genl_rcv_msg+0x432/0x6f0 netlink_rcv_skb+0x13d/0x3b0 genl_rcv+0x28/0x40 netlink_unicast+0x42e/0x720 netlink_sendmsg+0x765/0xc20 __sys_sendto+0x3ac/0x420 __x64_sys_sendto+0xe0/0x1c0 do_syscall_64+0x95/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e This is because unregister_netdevice_many_notify might run before the rtnl lock section of ethnl operations, eg. set_channels in the above example. In this example the rss lock would be destroyed by the device unregistration path before being used again, but in general running ethnl operations while dismantle has started is not a good idea. Fix this by denying any operation on devices being unregistered. A check was already there in ethnl_ops_begin, but not wide enough. Note that the same issue cannot be seen on the ioctl version (__dev_ethtool) because the device reference is retrieved from within the rtnl lock section there. Once dismantle started, the net device is unlisted and no reference will be found.
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
43 explicit affected versions
61 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
6 explicit affected versions
71 explicit affected versions
21 explicit affected versions
56 explicit affected versions
64 explicit affected versions
57 explicit affected versions
10 explicit affected versions
12 explicit affected versions
19 explicit affected versions
63 explicit affected versions
7 explicit affected versions
62 explicit affected versions
16 explicit affected versions
13 explicit affected versions
18 explicit affected versions
35 explicit affected versions
23 explicit affected versions
21 explicit affected versions
18 explicit affected versions
22 explicit affected versions
45 explicit affected versions
21 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
26 explicit affected versions
1 explicit affected versions
21 explicit affected versions
16 explicit affected versions
10 explicit affected versions
22 explicit affected versions
3 explicit affected versions
7 explicit affected versions
12 explicit affected versions
2 explicit affected versions
54 explicit affected versions
12 explicit affected versions
14 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
12 explicit affected versions
12 explicit affected versions
16 explicit affected versions
17 explicit affected versions
13 explicit affected versions
8 explicit affected versions
10 explicit affected versions
37 explicit affected versions
1 explicit affected versions
13 explicit affected versions
14 explicit affected versions
10 explicit affected versions
38 explicit affected versions
26 explicit affected versions
13 explicit affected versions
13 explicit affected versions
29 explicit affected versions
13 explicit affected versions
68 explicit affected versions
15 explicit affected versions
16 explicit affected versions
63 explicit affected versions
26 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
1 explicit affected versions
11 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
54 explicit affected versions
48 explicit affected versions
64 explicit affected versions
10 explicit affected versions
26 explicit affected versions
20 explicit affected versions
1 explicit affected versions
11 explicit affected versions
23 explicit affected versions
13 explicit affected versions
21 explicit affected versions
16 explicit affected versions
65 explicit affected versions
24 explicit affected versions
53 explicit affected versions
3 explicit affected versions
2 explicit affected versions
2 explicit affected versions
51 explicit affected versions
11 explicit affected versions
20 explicit affected versions
12 explicit affected versions
51 explicit affected versions
27 explicit affected versions
38 explicit affected versions
17 explicit affected versions
8 explicit affected versions
28 explicit affected versions
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
2 explicit affected versions
20 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
2 explicit affected versions
55 explicit affected versions
10 explicit affected versions
12 explicit affected versions
15 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
25 explicit affected versions
14 explicit affected versions
38 explicit affected versions
54 explicit affected versions
9 explicit affected versions
53 explicit affected versions
11 explicit affected versions
15 explicit affected versions
7 explicit affected versions
64 explicit affected versions
7 explicit affected versions
33 explicit affected versions
4 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
62 explicit affected versions
13 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
19 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
14 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: net: avoid race between device unregistration and ethnl ops The following trace can be seen if a device is being unregistered while its number of channels are being modified. DEBUG_LOCKS_WARN_ON(lock->magic != lock) WARNING: CPU: 3 PID: 3754 at kernel/locking/mutex.c:564 __mutex_lock+0xc8a/0x1120 CPU: 3 UID: 0 PID: 3754 Comm: ethtool Not tainted 6.13.0-rc6+ #771 RIP: 0010:__mutex_lock+0xc8a/0x1120 Call Trace: <TASK> ethtool_check_max_channel+0x1ea/0x880 ethnl_set_channels+0x3c3/0xb10 ethnl_default_set_doit+0x306/0x650 genl_family_rcv_msg_doit+0x1e3/0x2c0 genl_rcv_msg+0x432/0x6f0 netlink_rcv_skb+0x13d/0x3b0 genl_rcv+0x28/0x40 netlink_unicast+0x42e/0x720 netlink_sendmsg+0x765/0xc20 __sys_sendto+0x3ac/0x420 __x64_sys_sendto+0xe0/0x1c0 do_syscall_64+0x95/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e This is because unregister_netdevice_many_notify might run before the rtnl lock section of ethnl operations, eg. set_channels in the above example. In this example the rss lock would be destroyed by the device unregistration path before being used again, but in general running ethnl operations while dismantle has started is not a good idea. Fix this by denying any operation on devices being unregistered. A check was already there in ethnl_ops_begin, but not wide enough. Note that the same issue cannot be seen on the ioctl version (__dev_ethtool) because the device reference is retrieved from within the rtnl lock section there. Once dismantle started, the net device is unlisted and no reference will be found.
05 / REFERENCES
Further evidence
- https://git.kernel.org/stable/c/12e070eb6964b341b41677fd260af5a305316a1f
- https://git.kernel.org/stable/c/2f29127e94ae9fdc7497331003d6860e9551cdf3
- https://git.kernel.org/stable/c/4dc880245f9b529fa8f476b5553c799d2848b47b
- https://git.kernel.org/stable/c/b382ab9b885cbb665e0e70a727f101c981b4edf3
- https://ubuntu.com/security/CVE-2025-21701
- https://ubuntu.com/security/notices/USN-7445-1
- https://ubuntu.com/security/notices/USN-7448-1
- https://ubuntu.com/security/notices/USN-7449-1
- https://ubuntu.com/security/notices/USN-7449-2
- https://ubuntu.com/security/notices/USN-7450-1
- https://ubuntu.com/security/notices/USN-7451-1
- https://ubuntu.com/security/notices/USN-7452-1
- https://ubuntu.com/security/notices/USN-7453-1
- https://ubuntu.com/security/notices/USN-7455-1
- https://ubuntu.com/security/notices/USN-7455-2
- https://ubuntu.com/security/notices/USN-7455-3
- https://ubuntu.com/security/notices/USN-7455-4
- https://ubuntu.com/security/notices/USN-7455-5
- https://ubuntu.com/security/notices/USN-7459-1
- https://ubuntu.com/security/notices/USN-7459-2
- https://ubuntu.com/security/notices/USN-7460-1
- https://ubuntu.com/security/notices/USN-7468-1
- https://ubuntu.com/security/notices/USN-7475-1
- https://ubuntu.com/security/notices/USN-7523-1
- https://ubuntu.com/security/notices/USN-7524-1
- https://www.cve.org/CVERecord?id=CVE-2025-21701