PT-2024-11096 · Linux+2 · Linux Kernel+2
Michael Ellerman
·
Published
2021-05-14
·
Updated
2024-12-26
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CVE-2021-46990
CVSS v3.1
5.5
Medium
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel (affected versions not specified)
Description
The issue is related to the powerpc/64s architecture in the Linux kernel, where crashes can occur when toggling the entry flush barrier. The entry flush mitigation can be enabled or disabled at runtime via a debugfs file (entry flush), which causes the kernel to patch itself. However, depending on the mitigation used, it may not be safe to do this patching while other CPUs are active, leading to crashes such as a segfault with a corrupted LR pointing into the kernel. The fix involves doing the patching under stop machine, ensuring that CPUs not doing the patching spin in the core of the stop machine logic, which is sufficient because the patching does not affect that code.
Recommendations
At the moment, there is no information about a newer version that contains a fix for this vulnerability.
Exploit
RCE
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Weakness Enumeration
Related Identifiers
Affected Products
Linux Kernel
Suse
Ubuntu