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().
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Redhat_linux | — | No solution exists | Jul 21, 2026 | Jul 19, 2026 |
| Ubuntu | — | Upgrade linux-image-raspi-realtime-7.0Upgrade linux-image-7.0.0-1015-raspi-realtimeUpgrade linux-image-nvidiaUpgrade linux-image-nvidia-bos-64k-7.0Upgrade linux-image-ibmUpgrade linux-image-7.0.0-1015-raspiUpgrade linux-image-7.0.0-1009-aws-64kUpgrade linux-image-oracleUpgrade linux-image-azure-fde-7.0Upgrade linux-image-7.0.0-2016-nvidia-bosUpgrade linux-image-oracle-7.0Upgrade linux-image-nvidia-7.0Upgrade linux-image-nvidia-bosUpgrade linux-image-7.0.0-1011-gcp-64kUpgrade linux-image-gcp-7.0Upgrade linux-image-7.0.0-1009-awsUpgrade linux-image-7.0.0-2016-nvidia-bos-64kUpgrade linux-image-7.0.0-1008-oracle-64kUpgrade linux-image-7.0.0-1009-azure-fdeUpgrade linux-image-7.0.0-1011-gcpUpgrade linux-image-azure-fdeUpgrade linux-image-7.0.0-1010-azureUpgrade linux-image-aws-64k-7.0Upgrade linux-image-aws-7.0Upgrade linux-image-7.0.0-1016-nvidiaUpgrade linux-image-nvidia-64k-7.0Upgrade linux-image-ibm-7.0Upgrade linux-image-gcpUpgrade linux-image-raspiUpgrade linux-image-aws-64kUpgrade linux-image-raspi-realtimeUpgrade linux-image-oracle-64kUpgrade linux-image-raspi-7.0Upgrade linux-image-nvidia-bos-7.0Upgrade linux-image-awsUpgrade linux-image-gcp-64kUpgrade linux-image-azure-7.0Upgrade linux-image-oracle-64k-7.0Upgrade linux-image-azureUpgrade linux-image-7.0.0-1008-oracleUpgrade linux-image-nvidia-hwe-26.04Upgrade linux-image-nvidia-bos-64kUpgrade linux-image-7.0.0-1016-nvidia-64kUpgrade linux-image-nvidia-64k-hwe-26.04Upgrade linux-image-gcp-64k-7.0Upgrade linux-image-7.0.0-1010-ibmUpgrade linux-image-7.0.0-1014-azureUpgrade linux-image-nvidia-64k | Jul 21, 2026 | Jul 20, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Sep 21, 2026 | Jul 19, 2026 |
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