Bug 1225533 (CVE-2023-52831) - VUL-0: CVE-2023-52831: kernel: cpu/hotplug: don't offline the last non-isolated CPU
Summary: VUL-0: CVE-2023-52831: kernel: cpu/hotplug: don't offline the last non-isolat...
Status: NEW
Alias: CVE-2023-52831
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents (show other bugs)
Version: unspecified
Hardware: Other Other
: P3 - Medium : Normal
Target Milestone: ---
Assignee: Frederic Weisbecker
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/407210/
Whiteboard: CVSSv3.1:SUSE:CVE-2023-52831:5.5:(AV:...
Keywords:
Depends on:
Blocks:
 
Reported: 2024-05-28 19:16 UTC by SMASH SMASH
Modified: 2024-06-05 15:55 UTC (History)
3 users (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---


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Description SMASH SMASH 2024-05-28 19:16:38 UTC
In the Linux kernel, the following vulnerability has been resolved:

cpu/hotplug: Don't offline the last non-isolated CPU

If a system has isolated CPUs via the "isolcpus=" command line parameter,
then an attempt to offline the last housekeeping CPU will result in a
WARN_ON() when rebuilding the scheduler domains and a subsequent panic due
to and unhandled empty CPU mas in partition_sched_domains_locked().

cpuset_hotplug_workfn()
  rebuild_sched_domains_locked()
    ndoms = generate_sched_domains(&doms, &attr);
      cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_FLAG_DOMAIN));

Thus results in an empty CPU mask which triggers the warning and then the
subsequent crash:

WARNING: CPU: 4 PID: 80 at kernel/sched/topology.c:2366 build_sched_domains+0x120c/0x1408
Call trace:
 build_sched_domains+0x120c/0x1408
 partition_sched_domains_locked+0x234/0x880
 rebuild_sched_domains_locked+0x37c/0x798
 rebuild_sched_domains+0x30/0x58
 cpuset_hotplug_workfn+0x2a8/0x930

Unable to handle kernel paging request at virtual address fffe80027ab37080
 partition_sched_domains_locked+0x318/0x880
 rebuild_sched_domains_locked+0x37c/0x798

Aside of the resulting crash, it does not make any sense to offline the last
last housekeeping CPU.

Prevent this by masking out the non-housekeeping CPUs when selecting a
target CPU for initiating the CPU unplug operation via the work queue.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-52831
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2023/CVE-2023-52831.mbox
https://git.kernel.org/stable/c/3410b702354702b500bde10e3cc1f9db8731d908
https://git.kernel.org/stable/c/335a47ed71e332c82339d1aec0c7f6caccfcda13
https://git.kernel.org/stable/c/3073f6df783d9d75f7f69f73e16c7ef85d6cfb63
https://git.kernel.org/stable/c/38685e2a0476127db766f81b1c06019ddc4c9ffa
https://www.cve.org/CVERecord?id=CVE-2023-52831
https://bugzilla.redhat.com/show_bug.cgi?id=2282740