CVE-2025-21986

Source
https://nvd.nist.gov/vuln/detail/CVE-2025-21986
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21986.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-21986
Downstream
Related
Published
2025-04-01T15:47:12Z
Modified
2025-10-10T08:51:08.883080Z
Summary
net: switchdev: Convert blocking notification chain to a raw one
Details

In the Linux kernel, the following vulnerability has been resolved:

net: switchdev: Convert blocking notification chain to a raw one

A blocking notification chain uses a read-write semaphore to protect the integrity of the chain. The semaphore is acquired for writing when adding / removing notifiers to / from the chain and acquired for reading when traversing the chain and informing notifiers about an event.

In case of the blocking switchdev notification chain, recursive notifications are possible which leads to the semaphore being acquired twice for reading and to lockdep warnings being generated [1].

Specifically, this can happen when the bridge driver processes a SWITCHDEVBRPORTUNOFFLOADED event which causes it to emit notifications about deferred events when calling switchdevdeferredprocess().

Fix this by converting the notification chain to a raw notification chain in a similar fashion to the netdev notification chain. Protect the chain using the RTNL mutex by acquiring it when modifying the chain. Events are always informed under the RTNL mutex, but add an assertion in callswitchdevblocking_notifiers() to make sure this is not violated in the future.

Maintain the "blocking" prefix as events are always emitted from process context and listeners are allowed to block.

6.14.0-rc4-custom-g079270089484 #1 Not tainted

ip/52731 is trying to acquire lock: ffffffff850918d8 ((switchdevblockingnotifchain).rwsem){++++}-{4:4}, at: blockingnotifiercallchain+0x58/0xa0

but task is already holding lock: ffffffff850918d8 ((switchdevblockingnotifchain).rwsem){++++}-{4:4}, at: blockingnotifiercallchain+0x58/0xa0

other info that might help us debug this: Possible unsafe locking scenario:

CPU0

lock((switchdevblockingnotifchain).rwsem); lock((switchdevblockingnotifchain).rwsem);

* DEADLOCK * May be due to missing lock nesting notation 3 locks held by ip/52731: #0: ffffffff84f795b0 (rtnlmutex){+.+.}-{4:4}, at: rtnlnewlink+0x727/0x1dc0 #1: ffffffff8731f628 (&net->rtnlmutex){+.+.}-{4:4}, at: rtnlnewlink+0x790/0x1dc0 #2: ffffffff850918d8 ((switchdevblockingnotifchain).rwsem){++++}-{4:4}, at: blockingnotifiercallchain+0x58/0xa0

stack backtrace: ... ? _pfxdownread+0x10/0x10 ? _pfxmarklock+0x10/0x10 ? _pfxswitchdevportattrsetdeferred+0x10/0x10 blockingnotifiercallchain+0x58/0xa0 switchdevportattrnotify.constprop.0+0xb3/0x1b0 ? _pfxswitchdevportattrnotify.constprop.0+0x10/0x10 ? markheldlocks+0x94/0xe0 ? switchdevdeferredprocess+0x11a/0x340 switchdevportattrsetdeferred+0x27/0xd0 switchdevdeferredprocess+0x164/0x340 brswitchdevportunoffload+0xc8/0x100 [bridge] brswitchdevblockingevent+0x29f/0x580 [bridge] notifiercallchain+0xa2/0x440 blockingnotifiercallchain+0x6e/0xa0 switchdevbridgeport_unoffload+0xde/0x1a0 ...

References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
91ac2c79e896b28a4a3a262384689ee6dfeaf083
Fixed
af757f5ee3f754c5dceefb05c12ff37cb46fc682
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
a83856bd0c240267a86ce3388f3437d6ba5ac5ca
Fixed
1f7d051814e7a0cb1f0717ed5527c1059992129d
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
f7a70d650b0b6b0134ccba763d672c8439d9f09b
Fixed
a597d4b75669ec82c72cbee9fe75a15d04b35b2b
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
f7a70d650b0b6b0134ccba763d672c8439d9f09b
Fixed
f9ed3fb50b872bd78bcb01f25087f9e4e25085d8
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
f7a70d650b0b6b0134ccba763d672c8439d9f09b
Fixed
62531a1effa87bdab12d5104015af72e60d926ff
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
a7589eca09929c3cc2a62950ef7f40bcc58afe3a

Affected versions

v5.*

v5.10.1
v5.10.10
v5.10.11
v5.10.12
v5.10.13
v5.10.14
v5.10.15
v5.10.16
v5.10.17
v5.10.18
v5.10.19
v5.10.2
v5.10.3
v5.10.4
v5.10.5
v5.10.6
v5.10.7
v5.10.8
v5.10.9
v5.11.1
v5.11.10
v5.11.11
v5.11.12
v5.11.13
v5.11.14
v5.11.15
v5.11.16
v5.11.17
v5.11.18
v5.11.19
v5.11.2
v5.11.20
v5.11.21
v5.11.3
v5.11.4
v5.11.5
v5.11.6
v5.11.7
v5.11.8
v5.11.9
v5.12.1
v5.12.10
v5.12.11
v5.12.12
v5.12.13
v5.12.14
v5.12.15
v5.12.16
v5.12.17
v5.12.18
v5.12.19
v5.12.2
v5.12.3
v5.12.4
v5.12.5
v5.12.6
v5.12.7
v5.12.8
v5.12.9
v5.13.1
v5.13.10
v5.13.11
v5.13.12
v5.13.13
v5.13.14
v5.13.15
v5.13.16
v5.13.17
v5.13.18
v5.13.2
v5.13.3
v5.13.4
v5.13.5
v5.13.6
v5.13.7
v5.13.8
v5.13.9
v5.14.1
v5.14.10
v5.14.11
v5.14.12
v5.14.13
v5.14.14
v5.14.15
v5.14.16
v5.14.17
v5.14.18
v5.14.19
v5.14.2
v5.14.20
v5.14.3
v5.14.4
v5.14.5
v5.14.6
v5.14.7
v5.14.8
v5.14.9
v5.15.1
v5.15.10
v5.15.11
v5.15.12
v5.15.13
v5.15.14
v5.15.15
v5.15.16
v5.15.17
v5.15.18
v5.15.19
v5.15.2
v5.15.3
v5.15.4
v5.15.5
v5.15.6
v5.15.7
v5.15.8
v5.15.9
v5.16.1
v5.16.10
v5.16.11
v5.16.12
v5.16.13
v5.16.14
v5.16.15
v5.16.16
v5.16.17
v5.16.18
v5.16.19
v5.16.2
v5.16.20
v5.16.3
v5.16.4
v5.16.5
v5.16.6
v5.16.7
v5.16.8
v5.16.9
v5.17.1
v5.17.10
v5.17.11
v5.17.12
v5.17.13
v5.17.14
v5.17.2
v5.17.3
v5.17.4
v5.17.5
v5.17.6
v5.17.7
v5.17.8
v5.17.9
v5.18.1
v5.18.10
v5.18.11
v5.18.12
v5.18.13
v5.18.14
v5.18.15
v5.18.16
v5.18.17
v5.18.18
v5.18.19
v5.18.2
v5.18.3
v5.18.4
v5.18.5
v5.18.6
v5.18.7
v5.18.8
v5.18.9
v5.19.1
v5.19.10
v5.19.11
v5.19.12
v5.19.13
v5.19.14
v5.19.15
v5.19.16
v5.19.2
v5.19.3
v5.19.4
v5.19.5
v5.19.6
v5.19.7
v5.19.8
v5.19.9
v5.6.1
v5.6.10
v5.6.11
v5.6.12
v5.6.13
v5.6.14
v5.6.15
v5.6.16
v5.6.17
v5.6.18
v5.6.2
v5.6.3
v5.6.4
v5.6.5
v5.6.6
v5.6.7
v5.6.8
v5.6.9
v5.7.1
v5.7.10
v5.7.11
v5.7.12
v5.7.13
v5.7.14
v5.7.15
v5.7.16
v5.7.2
v5.7.3
v5.7.4
v5.7.5
v5.7.6
v5.7.7
v5.7.8
v5.7.9
v5.8.1
v5.8.10
v5.8.11
v5.8.12
v5.8.13
v5.8.14
v5.8.15
v5.8.16
v5.8.17
v5.8.18
v5.8.2
v5.8.3
v5.8.4
v5.8.5
v5.8.6
v5.8.7
v5.8.8
v5.8.9
v5.9.1
v5.9.10
v5.9.11
v5.9.12
v5.9.13
v5.9.14
v5.9.15
v5.9.16
v5.9.2
v5.9.3
v5.9.4
v5.9.5
v5.9.6
v5.9.7
v5.9.8
v5.9.9

v6.*

v6.0.1
v6.0.10
v6.0.11
v6.0.12
v6.0.13
v6.0.14
v6.0.15
v6.0.16
v6.0.17
v6.0.18
v6.0.2
v6.0.3
v6.0.4
v6.0.5
v6.0.6
v6.0.7
v6.0.8
v6.0.9
v6.1.1
v6.1.10
v6.1.100
v6.1.101
v6.1.102
v6.1.103
v6.1.104
v6.1.105
v6.1.106
v6.1.107
v6.1.108
v6.1.109
v6.1.11
v6.1.110
v6.1.111
v6.1.112
v6.1.113
v6.1.114
v6.1.115
v6.1.116
v6.1.117
v6.1.118
v6.1.119
v6.1.12
v6.1.120
v6.1.121
v6.1.122
v6.1.123
v6.1.124
v6.1.125
v6.1.126
v6.1.127
v6.1.128
v6.1.129
v6.1.13
v6.1.130
v6.1.131
v6.1.14
v6.1.15
v6.1.2
v6.1.3
v6.1.4
v6.1.5
v6.1.6
v6.1.7
v6.1.8
v6.1.80
v6.1.81
v6.1.82
v6.1.83
v6.1.84
v6.1.85
v6.1.86
v6.1.87
v6.1.88
v6.1.89
v6.1.9
v6.1.90
v6.1.91
v6.1.92
v6.1.93
v6.1.94
v6.1.95
v6.1.96
v6.1.97
v6.1.98
v6.1.99
v6.10
v6.10-rc1
v6.10-rc2
v6.10-rc3
v6.10-rc4
v6.10-rc5
v6.10-rc6
v6.10-rc7
v6.10.1
v6.10.10
v6.10.11
v6.10.12
v6.10.13
v6.10.2
v6.10.3
v6.10.4
v6.10.5
v6.10.6
v6.10.7
v6.10.8
v6.10.9
v6.11
v6.11-rc1
v6.11-rc2
v6.11-rc3
v6.11-rc4
v6.11-rc5
v6.11-rc6
v6.11-rc7
v6.11.1
v6.11.10
v6.11.11
v6.11.2
v6.11.3
v6.11.4
v6.11.5
v6.11.6
v6.11.7
v6.11.8
v6.11.9
v6.12
v6.12-rc1
v6.12-rc2
v6.12-rc3
v6.12-rc4
v6.12-rc5
v6.12-rc6
v6.12-rc7
v6.12.1
v6.12.10
v6.12.11
v6.12.12
v6.12.13
v6.12.14
v6.12.15
v6.12.16
v6.12.17
v6.12.18
v6.12.19
v6.12.2
v6.12.3
v6.12.4
v6.12.5
v6.12.6
v6.12.7
v6.12.8
v6.12.9
v6.13
v6.13-rc1
v6.13-rc2
v6.13-rc3
v6.13-rc4
v6.13-rc5
v6.13-rc6
v6.13-rc7
v6.13.1
v6.13.10
v6.13.11
v6.13.12
v6.13.2
v6.13.3
v6.13.4
v6.13.5
v6.13.6
v6.13.7
v6.13.8
v6.13.9
v6.14
v6.14-rc1
v6.14-rc2
v6.14-rc3
v6.14-rc4
v6.14-rc5
v6.14-rc6
v6.14-rc7
v6.14.1
v6.14.10
v6.14.11
v6.14.2
v6.14.3
v6.14.4
v6.14.5
v6.14.6
v6.14.7
v6.14.8
v6.14.9
v6.15
v6.15-rc1
v6.15-rc2
v6.15-rc3
v6.15-rc4
v6.15-rc5
v6.15-rc6
v6.15-rc7
v6.15.1
v6.15.10
v6.15.11
v6.15.2
v6.15.3
v6.15.4
v6.15.5
v6.15.6
v6.15.7
v6.15.8
v6.15.9
v6.16
v6.16-rc1
v6.16-rc2
v6.16-rc3
v6.16-rc4
v6.16-rc5
v6.16-rc6
v6.16-rc7
v6.16.1
v6.16.10
v6.16.11
v6.16.2
v6.16.3
v6.16.4
v6.16.5
v6.16.6
v6.16.7
v6.16.8
v6.16.9
v6.2.1
v6.2.10
v6.2.11
v6.2.12
v6.2.13
v6.2.14
v6.2.15
v6.2.2
v6.2.3
v6.2.4
v6.2.5
v6.2.6
v6.2.7
v6.2.8
v6.2.9
v6.3.1
v6.3.10
v6.3.11
v6.3.12
v6.3.2
v6.3.3
v6.3.4
v6.3.5
v6.3.6
v6.3.7
v6.3.8
v6.3.9
v6.4.1
v6.4.10
v6.4.11
v6.4.12
v6.4.13
v6.4.14
v6.4.15
v6.4.16
v6.4.2
v6.4.3
v6.4.4
v6.4.5
v6.4.6
v6.4.7
v6.4.8
v6.4.9
v6.5.1
v6.5.10
v6.5.11
v6.5.12
v6.5.13
v6.5.2
v6.5.3
v6.5.4
v6.5.5
v6.5.6
v6.5.7
v6.5.8
v6.5.9
v6.6.1
v6.6.10
v6.6.11
v6.6.12
v6.6.13
v6.6.14
v6.6.19
v6.6.2
v6.6.20
v6.6.21
v6.6.22
v6.6.23
v6.6.24
v6.6.25
v6.6.26
v6.6.27
v6.6.28
v6.6.29
v6.6.3
v6.6.30
v6.6.31
v6.6.32
v6.6.33
v6.6.34
v6.6.35
v6.6.36
v6.6.37
v6.6.38
v6.6.39
v6.6.4
v6.6.40
v6.6.41
v6.6.42
v6.6.43
v6.6.44
v6.6.45
v6.6.46
v6.6.47
v6.6.48
v6.6.49
v6.6.5
v6.6.50
v6.6.51
v6.6.52
v6.6.53
v6.6.54
v6.6.55
v6.6.56
v6.6.57
v6.6.58
v6.6.59
v6.6.6
v6.6.60
v6.6.61
v6.6.62
v6.6.63
v6.6.64
v6.6.65
v6.6.66
v6.6.67
v6.6.68
v6.6.69
v6.6.7
v6.6.70
v6.6.71
v6.6.72
v6.6.73
v6.6.74
v6.6.75
v6.6.76
v6.6.77
v6.6.78
v6.6.79
v6.6.8
v6.6.80
v6.6.81
v6.6.82
v6.6.83
v6.6.9
v6.7.10
v6.7.11
v6.7.12
v6.7.7
v6.7.8
v6.7.9
v6.8
v6.8-rc1
v6.8-rc2
v6.8-rc3
v6.8-rc4
v6.8-rc5
v6.8-rc6
v6.8-rc7
v6.8.1
v6.8.10
v6.8.11
v6.8.2
v6.8.3
v6.8.4
v6.8.5
v6.8.6
v6.8.7
v6.8.8
v6.8.9
v6.9
v6.9-rc1
v6.9-rc2
v6.9-rc3
v6.9-rc4
v6.9-rc5
v6.9-rc6
v6.9-rc7
v6.9.1
v6.9.10
v6.9.11
v6.9.12
v6.9.2
v6.9.3
v6.9.4
v6.9.5
v6.9.6
v6.9.7
v6.9.8
v6.9.9

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.1.132
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.84
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.20
Type
ECOSYSTEM
Events
Introduced
6.8.0
Fixed
6.13.8