Bug 2401563 (CVE-2022-50494)

Summary: CVE-2022-50494 kernel: thermal: intel_powerclamp: Use get_cpu() instead of smp_processor_id() to avoid crash
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-10-04 16:07:39 UTC 
In the Linux kernel, the following vulnerability has been resolved:

thermal: intel_powerclamp: Use get_cpu() instead of smp_processor_id() to avoid crash

When CPU 0 is offline and intel_powerclamp is used to inject
idle, it generates kernel BUG:

BUG: using smp_processor_id() in preemptible [00000000] code: bash/15687
caller is debug_smp_processor_id+0x17/0x20
CPU: 4 PID: 15687 Comm: bash Not tainted 5.19.0-rc7+ #57
Call Trace:
<TASK>
dump_stack_lvl+0x49/0x63
dump_stack+0x10/0x16
check_preemption_disabled+0xdd/0xe0
debug_smp_processor_id+0x17/0x20
powerclamp_set_cur_state+0x7f/0xf9 [intel_powerclamp]
...
...

Here CPU 0 is the control CPU by default and changed to the current CPU,
if CPU 0 offlined. This check has to be performed under cpus_read_lock(),
hence the above warning.

Use get_cpu() instead of smp_processor_id() to avoid this BUG.

[ rjw: Subject edits ]
Comment 1 Alexander B 2025-10-06 11:42:33 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100418-CVE-2022-50494-00a0@gregkh/T