Skip to content
Fencer Vulns
no cvss —

CVE-2025-68310 json

s390/pci: Avoid deadlock between PCI error recovery and mlx5 crdump

published 2025-12-16 10 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-203759

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

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

s390/pci: Avoid deadlock between PCI error recovery and mlx5 crdump

Do not block PCI config accesses through pci_cfg_access_lock() when executing the s390 variant of PCI error recovery: Acquire just device_lock() instead of pci_dev_lock() as powerpc's EEH and generig PCI AER processing do.

During error recovery testing a pair of tasks was reported to be hung:

mlx5_core 0000:00:00.1: mlx5_health_try_recover:338:(pid 5553): health recovery flow aborted, PCI reads still not working INFO: task kmcheck:72 blocked for more than 122 seconds. Not tainted 5.14.0-570.12.1.bringup7.el9.s390x #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kmcheck state:D stack:0 pid:72 tgid:72 ppid:2 flags:0x00000000 Call Trace: [<000000065256f030>] __schedule+0x2a0/0x590 [<000000065256f356>] schedule+0x36/0xe0 [<000000065256f572>] schedule_preempt_disabled+0x22/0x30 [<0000000652570a94>] __mutex_lock.constprop.0+0x484/0x8a8 [<000003ff800673a4>] mlx5_unload_one+0x34/0x58 [mlx5_core] [<000003ff8006745c>] mlx5_pci_err_detected+0x94/0x140 [mlx5_core] [<0000000652556c5a>] zpci_event_attempt_error_recovery+0xf2/0x398 [<0000000651b9184a>] __zpci_event_error+0x23a/0x2c0 INFO: task kworker/u1664:6:1514 blocked for more than 122 seconds. Not tainted 5.14.0-570.12.1.bringup7.el9.s390x #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u1664:6 state:D stack:0 pid:1514 tgid:1514 ppid:2 flags:0x00000000 Workqueue: mlx5_health0000:00:00.0 mlx5_fw_fatal_reporter_err_work [mlx5_core] Call Trace: [<000000065256f030>] __schedule+0x2a0/0x590 [<000000065256f356>] schedule+0x36/0xe0 [<0000000652172e28>] pci_wait_cfg+0x80/0xe8 [<0000000652172f94>] pci_cfg_access_lock+0x74/0x88 [<000003ff800916b6>] mlx5_vsc_gw_lock+0x36/0x178 [mlx5_core] [<000003ff80098824>] mlx5_crdump_collect+0x34/0x1c8 [mlx5_core] [<000003ff80074b62>] mlx5_fw_fatal_reporter_dump+0x6a/0xe8 [mlx5_core] [<0000000652512242>] devlink_health_do_dump.part.0+0x82/0x168 [<0000000652513212>] devlink_health_report+0x19a/0x230 [<000003ff80075a12>] mlx5_fw_fatal_reporter_err_work+0xba/0x1b0 [mlx5_core]

No kernel log of the exact same error with an upstream kernel is available - but the very same deadlock situation can be constructed there, too:

- task: kmcheck mlx5_unload_one() tries to acquire devlink lock while the PCI error recovery code has set pdev->block_cfg_access by way of pci_cfg_access_lock() - task: kworker mlx5_crdump_collect() tries to set block_cfg_access through pci_cfg_access_lock() while devlink_health_report() had acquired the devlink lock.

A similar deadlock situation can be reproduced by requesting a crdump with > devlink health dump show pci/<BDF> reporter fw_fatal

while PCI error recovery is executed on the same <BDF> physical function by mlx5_core's pci_error_handlers. On s390 this can be injected with > zpcictl --reset-fw <BDF>

Tests with this patch failed to reproduce that second deadlock situation, the devlink command is rejected with "kernel answers: Permission denied" - and we get a kernel log message of:

mlx5_core 1ed0:00:00.1: mlx5_crdump_collect:50:(pid 254382): crdump: failed to lock vsc gw err -5

because the config read of VSC_SEMAPHORE is rejected by the underlying hardware.

Two prior attempts to address this issue have been discussed and ultimately rejected [see link], with the primary argument that s390's implementation of PCI error recovery is imposing restrictions that neither powerpc's EEH nor PCI AER handling need. Tests show that PCI error recovery on s390 is running to completion even without blocking access to PCI config space.

Patch / fix

  • Linux Linux 6.1.159, 6.6.117, 6.12.58, 6.17.8, 6.18
  • linux Debian 12 6.1.159-1
  • linux Debian 13 6.12.63-1
  • linux Debian 14 6.17.8-1

debian advisories DEBIAN-CVE-2025-68310

  • linux Ubuntu 24.04 LTS 6.8.0-106.106
  • linux Ubuntu 25.10 6.17.0-14.14
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
  • linux-aws Ubuntu 25.10 6.17.0-1007.7
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55
  • linux-gcp Ubuntu 25.10 6.17.0-1007.7
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1048.53
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1049.49

ubuntu advisories UBUNTU-CVE-2025-68310

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-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.55.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.55.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.55.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.55.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.55.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.55.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.55.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.55.1.150700.17.33.1

suse advisories SUSE-SU-2026:2238-1SUSE-SU-2026:21834-1

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-2025-68310 updated cvss 5.5

kernel: Linux kernel: Denial of Service due to deadlock in PCI error recovery

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • 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
    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

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

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.