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CVE-2026-64070 (GCVE-0-2026-64070)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:39 – Updated: 2026-09-02 12:49
VLAI
Title
powerpc/hv-gpci: fix preempt count leak in sysfs show paths
Summary
In the Linux kernel, the following vulnerability has been resolved: powerpc/hv-gpci: fix preempt count leak in sysfs show paths Four sysfs show() callbacks in hv-gpci take get_cpu_var(hv_gpci_reqb) (which calls preempt_disable()) but only call the matching put_cpu_var() on the error path under the 'out:' label. Every successful read leaks one preempt_disable(): processor_bus_topology_show() processor_config_show() affinity_domain_via_virtual_processor_show() affinity_domain_via_domain_show() (affinity_domain_via_partition_show() was already correct.) On a CONFIG_PREEMPT=y kernel, repeated reads raise preempt_count and eventually return to userspace with preemption still disabled. The next user-mode page fault then hits faulthandler_disabled() == 1, gets forced to SIGSEGV, and the resulting coredump trips 'BUG: scheduling while atomic' in call_usermodehelper_exec -> wait_for_completion_state -> schedule: BUG: scheduling while atomic: <task>/<pid>/0x00000004 ... __schedule_bug+0x6c/0x90 __schedule+0x58c/0x13a0 schedule+0x48/0x1a0 schedule_timeout+0x104/0x170 wait_for_completion_state+0x16c/0x330 call_usermodehelper_exec+0x254/0x2d0 vfs_coredump+0x1050/0x2590 get_signal+0xb9c/0xc80 do_notify_resume+0xf8/0x470 Add an out_success label that calls put_cpu_var() before returning the byte count, mirroring affinity_domain_via_partition_show().
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 , < b300312562fd6e4729697adb9f777f00ca0429f3 (git)
Affected: 71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 , < 45afabe7f99c5d8746434ee41c86584c01d70147 (git)
Affected: 71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 , < b61ebb2826ca1852c2bbd92a676fb622c358cab4 (git)
Affected: 71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 , < 903409000a07ac8e31ffedeb8516f4f8d67150c8 (git)
Affected: 71f1c39647d8c9d4d54a861ec81f1ff17544bcb6 , < dbc30a57bd8e026995e9fa8e8c31cffd18542c01 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.6
Unaffected: 0 , < 6.6 (semver)
Unaffected: 6.6.156 , ≤ 6.6.* (semver)
Unaffected: 6.12.108 , ≤ 6.12.* (semver)
Unaffected: 6.18.49 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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