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CVE-2022-50177 Affecting kernel-doc package, versions *

Severity

 Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.02% (3rd percentile)

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  • Snyk IDSNYK-RHEL8-KERNELDOC-10523122
  • published26 Jun 2025
  • disclosed18 Jun 2025
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Introduced: 18 Jun 2025

NewCVE-2022-50177  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:8 kernel-doc.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-doc package and not the kernel-doc 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:

rcutorture: Fix ksoftirqd boosting timing and iteration

The RCU priority boosting can fail in two situations:

  1. If (nr_cpus= > maxcpus=), which means if the total number of CPUs is higher than those brought online at boot, then torture_onoff() may later bring up CPUs that weren't online on boot. Now since rcutorture initialization only boosts the ksoftirqds of the CPUs that have been set online on boot, the CPUs later set online by torture_onoff won't benefit from the boost, making RCU priority boosting fail.

  2. The ksoftirqd kthreads are boosted after the creation of rcu_torture_boost() kthreads, which opens a window large enough for these rcu_torture_boost() kthreads to wait (despite running at FIFO priority) for ksoftirqds that are still running at SCHED_NORMAL priority.

The issues can trigger for example with:

./kvm.sh --configs TREE01 --kconfig "CONFIG_RCU_BOOST=y"


[   34.968561] rcu-torture: !!!
[   34.968627] ------------[ cut here ]------------
[   35.014054] WARNING: CPU: 4 PID: 114 at kernel/rcu/rcutorture.c:1979 rcu_torture_stats_print+0x5ad/0x610
[   35.052043] Modules linked in:
[   35.069138] CPU: 4 PID: 114 Comm: rcu_torture_sta Not tainted 5.18.0-rc1 #1
[   35.096424] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
[   35.154570] RIP: 0010:rcu_torture_stats_print+0x5ad/0x610
[   35.198527] Code: 63 1b 02 00 74 02 0f 0b 48 83 3d 35 63 1b 02 00 74 02 0f 0b 48 83 3d 21 63 1b 02 00 74 02 0f 0b 48 83 3d 0d 63 1b 02 00 74 02 <0f> 0b 83 eb 01 0f 8e ba fc ff ff 0f 0b e9 b3 fc ff f82
[   37.251049] RSP: 0000:ffffa92a0050bdf8 EFLAGS: 00010202
[   37.277320] rcu: De-offloading 8
[   37.290367] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001
[   37.290387] RDX: 0000000000000000 RSI: 00000000ffffbfff RDI: 00000000ffffffff
[   37.290398] RBP: 000000000000007b R08: 0000000000000000 R09: c0000000ffffbfff
[   37.290407] R10: 000000000000002a R11: ffffa92a0050bc18 R12: ffffa92a0050be20
[   37.290417] R13: ffffa92a0050be78 R14: 0000000000000000 R15: 000000000001bea0
[   37.290427] FS:  0000000000000000(0000) GS:ffff96045eb00000(0000) knlGS:0000000000000000
[   37.290448] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   37.290460] CR2: 0000000000000000 CR3: 000000001dc0c000 CR4: 00000000000006e0
[   37.290470] Call Trace:
[   37.295049]  <TASK>
[   37.295065]  ? preempt_count_add+0x63/0x90
[   37.295095]  ? _raw_spin_lock_irqsave+0x12/0x40
[   37.295125]  ? rcu_torture_stats_print+0x610/0x610
[   37.295143]  rcu_torture_stats+0x29/0x70
[   37.295160]  kthread+0xe3/0x110
[   37.295176]  ? kthread_complete_and_exit+0x20/0x20
[   37.295193]  ret_from_fork+0x22/0x30
[   37.295218]  </TASK>

Fix this with boosting the ksoftirqds kthreads from the boosting hotplug callback itself and before the boosting kthreads are created.

CVSS Base Scores

version 3.1