Loop with Unreachable Exit Condition ('Infinite Loop') Affecting kernel-rt-debug-kvm package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

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  • Snyk IDSNYK-RHEL7-KERNELRTDEBUGKVM-9454416
  • published15 Mar 2025
  • disclosed12 Mar 2025

Introduced: 12 Mar 2025

NewCVE-2025-21850  (opens in a new tab)
CWE-835  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:7 kernel-rt-debug-kvm.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-debug-kvm package and not the kernel-rt-debug-kvm package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

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

nvmet: Fix crash when a namespace is disabled

The namespace percpu counter protects pending I/O, and we can only safely diable the namespace once the counter drop to zero. Otherwise we end up with a crash when running blktests/nvme/058 (eg for loop transport):

[ 2352.930426] [ T53909] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI [ 2352.930431] [ T53909] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] [ 2352.930434] [ T53909] CPU: 3 UID: 0 PID: 53909 Comm: kworker/u16:5 Tainted: G W 6.13.0-rc6 #232 [ 2352.930438] [ T53909] Tainted: [W]=WARN [ 2352.930440] [ T53909] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 [ 2352.930443] [ T53909] Workqueue: nvmet-wq nvme_loop_execute_work [nvme_loop] [ 2352.930449] [ T53909] RIP: 0010:blkcg_set_ioprio+0x44/0x180

as the queue is already torn down when calling submit_bio();

So we need to init the percpu counter in nvmet_ns_enable(), and wait for it to drop to zero in nvmet_ns_disable() to avoid having I/O pending after the namespace has been disabled.

CVSS Base Scores

version 3.1