CVE-2024-42126

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Source
https://cve.org/CVERecord?id=CVE-2024-42126
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-42126.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2024-42126
Downstream
Related
Published
2024-07-30T07:46:23Z
Modified
2026-08-12T03:30:38Z
Summary
powerpc: Avoid nmi_enter/nmi_exit in real mode interrupt.
Details

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

powerpc: Avoid nmi_enter/nmi_exit in real mode interrupt.

nmi_enter()/nmi_exit() touches per cpu variables which can lead to kernel crash when invoked during real mode interrupt handling (e.g. early HMI/MCE interrupt handler) if percpu allocation comes from vmalloc area.

Early HMI/MCE handlers are called through DEFINE_INTERRUPT_HANDLER_NMI() wrapper which invokes nmi_enter/nmi_exit calls. We don't see any issue when percpu allocation is from the embedded first chunk. However with CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK enabled there are chances where percpu allocation can come from the vmalloc area.

With kernel command line "percpu_alloc=page" we can force percpu allocation to come from vmalloc area and can see kernel crash in machine_check_early:

[ 1.215714] NIP [c000000000e49eb4] rcu_nmi_enter+0x24/0x110 [ 1.215717] LR [c0000000000461a0] machine_check_early+0xf0/0x2c0 [ 1.215719] --- interrupt: 200 [ 1.215720] [c000000fffd73180] [0000000000000000] 0x0 (unreliable) [ 1.215722] [c000000fffd731b0] [0000000000000000] 0x0 [ 1.215724] [c000000fffd73210] [c000000000008364] machine_check_early_common+0x134/0x1f8

Fix this by avoiding use of nmi_enter()/nmi_exit() in real mode if percpu first chunk is not embedded.

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/42xxx/CVE-2024-42126.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
eb553f16973ade990d05946af9ae191394712c8a
Fixed
fb6675db04c4b79883373edc578d5df7bbc84848
Fixed
e2afb26615adf6c3ceaaa7732aa839bcd587a057
Fixed
8d3f83dfb23674540c827a8d65fba20aa300b252
Fixed
0f37946c62c48a907625348cbc720a7a0c547d1e
Fixed
2c78c9411e685dbc9eac8c2845111b03501975b8
Fixed
0db880fc865ffb522141ced4bfa66c12ab1fbb70

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-42126.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
5.10.0
Fixed
5.10.224
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.165
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.98
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.39
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.9.9

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-42126.json"