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Fencer Vulns
medium 5.5

CVE-2024-26725 json

dpll: fix possible deadlock during netlink dump operation

published 2024-04-03 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-23987

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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

dpll: fix possible deadlock during netlink dump operation

Recently, I've been hitting following deadlock warning during dpll pin dump:

[52804.637962] ====================================================== [52804.638536] WARNING: possible circular locking dependency detected [52804.639111] 6.8.0-rc2jiri+ #1 Not tainted [52804.639529] ------------------------------------------------------ [52804.640104] python3/2984 is trying to acquire lock: [52804.640581] ffff88810e642678 (nlk_cb_mutex-GENERIC){+.+.}-{3:3}, at: netlink_dump+0xb3/0x780 [52804.641417] but task is already holding lock: [52804.642010] ffffffff83bde4c8 (dpll_lock){+.+.}-{3:3}, at: dpll_lock_dumpit+0x13/0x20 [52804.642747] which lock already depends on the new lock.

[52804.643551] the existing dependency chain (in reverse order) is: [52804.644259] -> #1 (dpll_lock){+.+.}-{3:3}: [52804.644836] lock_acquire+0x174/0x3e0 [52804.645271] __mutex_lock+0x119/0x1150 [52804.645723] dpll_lock_dumpit+0x13/0x20 [52804.646169] genl_start+0x266/0x320 [52804.646578] __netlink_dump_start+0x321/0x450 [52804.647056] genl_family_rcv_msg_dumpit+0x155/0x1e0 [52804.647575] genl_rcv_msg+0x1ed/0x3b0 [52804.648001] netlink_rcv_skb+0xdc/0x210 [52804.648440] genl_rcv+0x24/0x40 [52804.648831] netlink_unicast+0x2f1/0x490 [52804.649290] netlink_sendmsg+0x36d/0x660 [52804.649742] __sock_sendmsg+0x73/0xc0 [52804.650165] __sys_sendto+0x184/0x210 [52804.650597] __x64_sys_sendto+0x72/0x80 [52804.651045] do_syscall_64+0x6f/0x140 [52804.651474] entry_SYSCALL_64_after_hwframe+0x46/0x4e [52804.652001] -> #0 (nlk_cb_mutex-GENERIC){+.+.}-{3:3}: [52804.652650] check_prev_add+0x1ae/0x1280 [52804.653107] __lock_acquire+0x1ed3/0x29a0 [52804.653559] lock_acquire+0x174/0x3e0 [52804.653984] __mutex_lock+0x119/0x1150 [52804.654423] netlink_dump+0xb3/0x780 [52804.654845] __netlink_dump_start+0x389/0x450 [52804.655321] genl_family_rcv_msg_dumpit+0x155/0x1e0 [52804.655842] genl_rcv_msg+0x1ed/0x3b0 [52804.656272] netlink_rcv_skb+0xdc/0x210 [52804.656721] genl_rcv+0x24/0x40 [52804.657119] netlink_unicast+0x2f1/0x490 [52804.657570] netlink_sendmsg+0x36d/0x660 [52804.658022] __sock_sendmsg+0x73/0xc0 [52804.658450] __sys_sendto+0x184/0x210 [52804.658877] __x64_sys_sendto+0x72/0x80 [52804.659322] do_syscall_64+0x6f/0x140 [52804.659752] entry_SYSCALL_64_after_hwframe+0x46/0x4e [52804.660281] other info that might help us debug this:

[52804.661077] Possible unsafe locking scenario:

[52804.661671] CPU0 CPU1 [52804.662129] ---- ---- [52804.662577] lock(dpll_lock); [52804.662924] lock(nlk_cb_mutex-GENERIC); [52804.663538] lock(dpll_lock); [52804.664073] lock(nlk_cb_mutex-GENERIC); [52804.664490]

The issue as follows: __netlink_dump_start() calls control->start(cb) with nlk->cb_mutex held. In control->start(cb) the dpll_lock is taken. Then nlk->cb_mutex is released and taken again in netlink_dump(), while dpll_lock still being held. That leads to ABBA deadlock when another CPU races with the same operation.

Fix this by moving dpll_lock taking into dumpit() callback which ensures correct lock taking order.

Patch / fix

  • Linux Linux 6.7.6, 6.8
  • linux Debian 14, Debian 13 6.7.7-1

debian advisories DEBIAN-CVE-2024-26725

  • linux-bluefield Ubuntu Nvidia-BlueField 22.04 LTS 5.15.0-1044.46
  • linux-raspi-realtime Ubuntu Pro Realtime 24.04 LTS 6.8.0-2002.2

ubuntu advisories UBUNTU-CVE-2024-26725

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-503.11.1.el9_5
  • rv RHEL 9 5.14.0-503.11.1.el9_5
  • perf RHEL 9 5.14.0-503.11.1.el9_5
  • rtla RHEL 9 5.14.0-503.11.1.el9_5
  • bpftool RHEL 9 7.4.0-503.11.1.el9_5
  • libperf RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-rt RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-64k RHEL 9 5.14.0-503.11.1.el9_5

red hat advisories RHSA-2024:9315

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-26725 updated cvss 4.4

kernel: dpll: fix possible deadlock during netlink dump operation

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available
  • Red Hat CodeReady Linux Builder (v. 9) libperf 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-s390x 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-x86_64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-aarch64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-ppc64le 5.14.0-503.11.1.el9_5 Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-503.11.1.el9_5, perf 5.14.0-503.11.1.el9_5, rtla 5.14.0-503.11.1.el9_5, kernel-devel-matched 5.14.0-503.11.1.el9_5, kernel-64k-devel-matched 5.14.0-503.11.1.el9_5, kernel-debug-devel-matched 5.14.0-503.11.1.el9_5, +6 more Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.4.0-503.11.1.el9_5, kernel 5.14.0-503.11.1.el9_5, kernel-64k 5.14.0-503.11.1.el9_5, kernel-core 5.14.0-503.11.1.el9_5, kernel-tools 5.14.0-503.11.1.el9_5, python3-perf 5.14.0-503.11.1.el9_5, +29 more Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, kernel-rt-modules-core 5.14.0-503.11.1.el9_5, kernel-rt-debug-modules 5.14.0-503.11.1.el9_5, +4 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-kvm 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-kvm 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, +6 more
    fixed: vendor fix RHSA-2024:9315
  • Red Hat CodeReady Linux Builder (v. 9) kernel-cross-headers 5.14.0-503.11.1.el9_5 Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux AppStream (v. 9) kernel-headers 5.14.0-503.11.1.el9_5
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.