can: j1939: implement NETDEV_UNREGISTER notification handler
syzbot is reporting
unregister_netdevice: waiting for vcan0 to become free. Usage count = 2
problem, for j1939 protocol did not have NETDEV_UNREGISTER notification
handler for undoing changes made by j1939_sk_bind().
Commit 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct
callback") expects that a call to j1939_priv_put() can be unconditionally
delayed until j1939_sk_sock_destruct() is called. But we need to call
j1939_priv_put() against an extra ref held by j1939_sk_bind() call
(as a part of undoing changes made by j1939_sk_bind()) as soon as
NETDEV_UNREGISTER notification fires (i.e. before j1939_sk_sock_destruct()
is called via j1939_sk_release()). Otherwise, the extra ref on "struct
j1939_priv" held by j1939_sk_bind() call prevents "struct net_device" from
dropping the usage count to 1; making it impossible for
unregister_netdevice() to continue.
[mkl: remove space in front of label]
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Wed, 14 Jan 2026 18:15:00 +0000
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ssvc
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Thu, 11 Dec 2025 18:30:00 +0000
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| Weaknesses | NVD-CWE-noinfo | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* |
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| Metrics |
cvssV3_1
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cvssV3_1
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Fri, 03 Oct 2025 00:15:00 +0000
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| Metrics |
threat_severity
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cvssV3_1
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Thu, 02 Oct 2025 09:00:00 +0000
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| First Time appeared |
Linux
Linux linux Kernel |
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| Vendors & Products |
Linux
Linux linux Kernel |
Wed, 01 Oct 2025 08:15:00 +0000
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| Description | In the Linux kernel, the following vulnerability has been resolved: can: j1939: implement NETDEV_UNREGISTER notification handler syzbot is reporting unregister_netdevice: waiting for vcan0 to become free. Usage count = 2 problem, for j1939 protocol did not have NETDEV_UNREGISTER notification handler for undoing changes made by j1939_sk_bind(). Commit 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct callback") expects that a call to j1939_priv_put() can be unconditionally delayed until j1939_sk_sock_destruct() is called. But we need to call j1939_priv_put() against an extra ref held by j1939_sk_bind() call (as a part of undoing changes made by j1939_sk_bind()) as soon as NETDEV_UNREGISTER notification fires (i.e. before j1939_sk_sock_destruct() is called via j1939_sk_release()). Otherwise, the extra ref on "struct j1939_priv" held by j1939_sk_bind() call prevents "struct net_device" from dropping the usage count to 1; making it impossible for unregister_netdevice() to continue. [mkl: remove space in front of label] | |
| Title | can: j1939: implement NETDEV_UNREGISTER notification handler | |
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:39:04.692Z
Reserved: 2025-04-16T07:20:57.147Z
Link: CVE-2025-39925
Updated: 2026-01-14T17:39:00.721Z
Status : Modified
Published: 2025-10-01T08:15:35.857
Modified: 2026-01-14T18:16:40.930
Link: CVE-2025-39925
OpenCVE Enrichment
Updated: 2025-10-02T08:40:09Z