Medium severity · published Sep 11, 2025
CVE-2025-39736
mm/kmemleak: avoid deadlock by moving pr_warn() outside kmemleak_lock
5.5
CVSS
0.1%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
mm/kmemleak: avoid deadlock by moving pr_warn() outside kmemleak_lock
When netpoll is enabled, calling pr_warn_once() while holding
kmemleak_lock in mem_pool_alloc() can cause a deadlock due to lock
inversion with the netconsole subsystem. This occurs because
pr_warn_once() may trigger netpoll, which eventually leads to
__alloc_skb() and back into kmemleak code, attempting to reacquire
kmemleak_lock.
This is the path for the deadlock.
mem_pool_alloc()
-> raw_spin_lock_irqsave(&kmemleak_lock, flags);
-> pr_warn_once()
-> netconsole subsystem
-> netpoll
-> __alloc_skb
-> __create_object
-> raw_spin_lock_irqsave(&kmemleak_lock, flags);
Fix this by setting a flag and issuing the pr_warn_once() after
kmemleak_lock is released.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 3% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
5.4 before 5.4.297; 5.5 before 5.10.241; 5.11 before 5.15.190; 5.16 before 6.1.149; 6.2 before 6.6.103; 6.7 before 6.12.43; +3 more · source: NVD
LI
Linux · Linux
c5665868183fec689dbab9fb8505188b2c4f0757 before c7b6ea0ede687e7460e593c5ea478f50aa41682a; c5665868183fec689dbab9fb8505188b2c4f0757 before 4b0151e1d468eb2667c37b7af99b3c075072d334; c5665868183fec689dbab9fb8505188b2c4f0757 before f249d32bb54876b4b6c3ae071af8ddca77af390b; c5665868183fec689dbab9fb8505188b2c4f0757 before 62879faa8efe8d8a9c7bf7606ee9c068012d7dac; c5665868183fec689dbab9fb8505188b2c4f0757 before 1da95d3d4b7b1d380ebd87b71a61e7e6aed3265d; c5665868183fec689dbab9fb8505188b2c4f0757 before a0854de00ce2ee27edf39037e7836ad580eb3350; +4 more · source: vendor
DL
Debian Linux · Debian
11.0 · source: NVD
SC
SIMATIC CN 4100 · Siemens
before V5.0 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-39736
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-39736
Patch
https://git.kernel.org/stable/c/08f70be5e406ce47c822f2dd11c1170ca259605b
Patch
https://git.kernel.org/stable/c/1da95d3d4b7b1d380ebd87b71a61e7e6aed3265d
Patch
https://git.kernel.org/stable/c/47b0f6d8f0d2be4d311a49e13d2fd5f152f492b2
Patch
https://git.kernel.org/stable/c/4b0151e1d468eb2667c37b7af99b3c075072d334
Patch
https://git.kernel.org/stable/c/62879faa8efe8d8a9c7bf7606ee9c068012d7dac
Patch
https://git.kernel.org/stable/c/a0854de00ce2ee27edf39037e7836ad580eb3350
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