Bug 2532225 (CVE-2026-81015)

Summary: CVE-2026-81015 kernel: platform/x86/amd/pmc: Fix LPS0 and debugfs leaks when STB init fails
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's AMD PMC (Power Management Controller) driver. When the `amd_stb_s2d_init()` function fails during the driver's initialization process, it can lead to unreleased resources, specifically the LPS0 s2idle handler and debugfs directory. This resource leak can corrupt internal lists, potentially causing a kernel crash and a denial of service if the module is reloaded. Additionally, stale registrations can lead to issues during subsequent system suspend-to-idle transitions.
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Description OSIDB Bzimport 2026-09-11 21:30:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

platform/x86/amd/pmc: Fix LPS0 and debugfs leaks when STB init fails

amd_pmc_probe() registers the LPS0 s2idle handler with
acpi_register_lps0_dev() and creates the driver's debugfs directory before
calling amd_stb_s2d_init(), which is the last step in probe that can fail.

When amd_stb_s2d_init() fails (for example the S2D telemetry region cannot
be ioremapped on a long-running system, or the SMU rejects the S2D setup)
the error path only calls pci_dev_put() and returns.  This leaves
amd_pmc_s2idle_dev_ops on the global lps0_s2idle_devops_head list and leaks
the debugfs directory, while the devm-managed resources backing the handler
are torn down.

Reloading the module then walks the corrupted list in
acpi_register_lps0_dev() and hits:

  list_add corruption. next->prev should be prev, but was NULL.
  kernel BUG at lib/list_debug.c:29!
   acpi_register_lps0_dev+0x44/0x80
   amd_pmc_probe+0x224/0x380 [amd_pmc]
   platform_probe+0x67/0x90

Even without a reload, the stale registration means the next s2idle
transition calls into torn-down driver state.

Unwind the debugfs directory and the LPS0 registration on the
amd_stb_s2d_init() error path.  acpi_unregister_lps0_dev() is safe to call
unconditionally here: it is guarded on the same conditions as
acpi_register_lps0_dev(), which is exactly what amd_pmc_remove() already
relies on.
Comment 1 Keith Grant 2026-09-14 21:05:37 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-81015.mbox