CVE-2023-53291

/// Technical description

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

rcu/rcuscale: Stop kfree_scale_thread thread(s) after unloading rcuscale

Running the 'kfree_rcu_test' test case [1] results in a splat [2].

The root cause is the kfree_scale_thread thread(s) continue running

after unloading the rcuscale module. This commit fixes that isue by

invoking kfree_scale_cleanup() from rcu_scale_cleanup() when removing

the rcuscale module.

[1] modprobe rcuscale kfree_rcu_test=1

// After some time

rmmod rcuscale

rmmod torture

[2] BUG: unable to handle page fault for address: ffffffffc0601a87

#PF: supervisor instruction fetch in kernel mode

#PF: error_code(0x0010) - not-present page

PGD 11de4f067 P4D 11de4f067 PUD 11de51067 PMD 112f4d067 PTE 0

Oops: 0010 [#1] PREEMPT SMP NOPTI

CPU: 1 PID: 1798 Comm: kfree_scale_thr Not tainted 6.3.0-rc1-rcu+ #1

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015

RIP: 0010:0xffffffffc0601a87

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References