CVE-2022-50296
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-15

Last updated on: 2025-12-04

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: UM: cpuinfo: Fix a warning for CONFIG_CPUMASK_OFFSTACK When CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS is selected, cpu_max_bits_warn() generates a runtime warning similar as below while we show /proc/cpuinfo. Fix this by using nr_cpu_ids (the runtime limit) instead of NR_CPUS to iterate CPUs. [ 3.052463] ------------[ cut here ]------------ [ 3.059679] WARNING: CPU: 3 PID: 1 at include/linux/cpumask.h:108 show_cpuinfo+0x5e8/0x5f0 [ 3.070072] Modules linked in: efivarfs autofs4 [ 3.076257] CPU: 0 PID: 1 Comm: systemd Not tainted 5.19-rc5+ #1052 [ 3.099465] Stack : 9000000100157b08 9000000000f18530 9000000000cf846c 9000000100154000 [ 3.109127] 9000000100157a50 0000000000000000 9000000100157a58 9000000000ef7430 [ 3.118774] 90000001001578e8 0000000000000040 0000000000000020 ffffffffffffffff [ 3.128412] 0000000000aaaaaa 1ab25f00eec96a37 900000010021de80 900000000101c890 [ 3.138056] 0000000000000000 0000000000000000 0000000000000000 0000000000aaaaaa [ 3.147711] ffff8000339dc220 0000000000000001 0000000006ab4000 0000000000000000 [ 3.157364] 900000000101c998 0000000000000004 9000000000ef7430 0000000000000000 [ 3.167012] 0000000000000009 000000000000006c 0000000000000000 0000000000000000 [ 3.176641] 9000000000d3de08 9000000001639390 90000000002086d8 00007ffff0080286 [ 3.186260] 00000000000000b0 0000000000000004 0000000000000000 0000000000071c1c [ 3.195868] ... [ 3.199917] Call Trace: [ 3.203941] [<90000000002086d8>] show_stack+0x38/0x14c [ 3.210666] [<9000000000cf846c>] dump_stack_lvl+0x60/0x88 [ 3.217625] [<900000000023d268>] __warn+0xd0/0x100 [ 3.223958] [<9000000000cf3c90>] warn_slowpath_fmt+0x7c/0xcc [ 3.231150] [<9000000000210220>] show_cpuinfo+0x5e8/0x5f0 [ 3.238080] [<90000000004f578c>] seq_read_iter+0x354/0x4b4 [ 3.245098] [<90000000004c2e90>] new_sync_read+0x17c/0x1c4 [ 3.252114] [<90000000004c5174>] vfs_read+0x138/0x1d0 [ 3.258694] [<90000000004c55f8>] ksys_read+0x70/0x100 [ 3.265265] [<9000000000cfde9c>] do_syscall+0x7c/0x94 [ 3.271820] [<9000000000202fe4>] handle_syscall+0xc4/0x160 [ 3.281824] ---[ end trace 8b484262b4b8c24c ]---
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Meta Information
Published
2025-09-15
Last Modified
2025-12-04
Generated
2026-06-16
AI Q&A
2025-09-15
EPSS Evaluated
2026-06-15
NVD
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel to 4.9.331 (exc)
linux linux_kernel From 4.10 (inc) to 4.14.296 (exc)
linux linux_kernel From 4.15 (inc) to 4.19.262 (exc)
linux linux_kernel From 4.20 (inc) to 5.4.220 (exc)
linux linux_kernel From 5.5 (inc) to 5.10.150 (exc)
linux linux_kernel From 5.11 (inc) to 5.15.75 (exc)
linux linux_kernel From 5.16 (inc) to 5.19.17 (exc)
linux linux_kernel From 6.0 (inc) to 6.0.3 (exc)
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Executive Summary

This vulnerability is a runtime warning in the Linux kernel related to the way CPU information is shown in /proc/cpuinfo when certain kernel configuration options (CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS) are enabled. The issue occurs because the kernel code uses a fixed constant (NR_CPUS) instead of the runtime limit (nr_cpu_ids) to iterate over CPUs, which causes a warning to be generated. The fix involves changing the code to use the runtime limit to avoid this warning.

Impact Analysis

This vulnerability causes a runtime warning in the kernel logs when viewing CPU information, which may lead to confusion or concern about kernel stability or correctness. However, it does not indicate a security breach or direct impact on system functionality or security.

Detection Guidance

This vulnerability can be detected by checking for runtime warnings related to CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS in the kernel logs, specifically warnings generated by cpu_max_bits_warn() when showing /proc/cpuinfo. You can use the command 'dmesg | grep WARNING' or 'journalctl -k | grep WARNING' to look for such warnings in the system logs.

Mitigation Strategies

Immediate mitigation involves updating the Linux kernel to a version where this issue is fixed, which uses nr_cpu_ids instead of NR_CPUS to iterate CPUs and prevents the runtime warning. Until then, monitoring for the warning and avoiding configurations that enable both CONFIG_CPUMASK_OFFSTACK and CONFIG_DEBUG_PER_CPU_MAPS simultaneously may reduce exposure.

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