Deadlock Affecting kernel-core package, versions <0:4.18.0-305.139.1.el8_4


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELCORE-7884938
  • published3 Sept 2024
  • disclosed12 Jul 2024

Introduced: 12 Jul 2024

CVE-2024-40995  (opens in a new tab)
CWE-833  (opens in a new tab)

How to fix?

Upgrade RHEL:8 kernel-core to version 0:4.18.0-305.139.1.el8_4 or higher.
This issue was patched in RHSA-2024:6156.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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

net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()

syzbot found hanging tasks waiting on rtnl_lock [1]

A reproducer is available in the syzbot bug.

When a request to add multiple actions with the same index is sent, the second request will block forever on the first request. This holds rtnl_lock, and causes tasks to hang.

Return -EAGAIN to prevent infinite looping, while keeping documented behavior.

[1]

INFO: task kworker/1:0:5088 blocked for more than 143 seconds. Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:0 state:D stack:23744 pid:5088 tgid:5088 ppid:2 flags:0x00004000 Workqueue: events_power_efficient reg_check_chans_work Call Trace: <TASK> context_switch kernel/sched/core.c:5409 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6746 __schedule_loop kernel/sched/core.c:6823 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6838 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6895 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 wiphy_lock include/net/cfg80211.h:5953 [inline] reg_leave_invalid_chans net/wireless/reg.c:2466 [inline] reg_check_chans_work+0x10a/0x10e0 net/wireless/reg.c:2481

CVSS Scores

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