Bug 2532530 (CVE-2026-89459)
| Summary: | CVE-2026-89459 kernel: s390/percpu: Fix MVIY_PERCPU() with older binutils | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability-draft | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | 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 |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
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| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel's s390/percpu component. This vulnerability arises when the kernel is compiled with older versions of GNU as (prior to binutils 2.39). A parsing error prevents a crucial instruction from being correctly processed, which can lead to issues with system resource management after a process migrates between CPUs. This can result in system instability and potentially a Denial of Service (DoS).
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Story Points: | --- |
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| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
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In the Linux kernel, the following vulnerability has been resolved: s390/percpu: Fix MVIY_PERCPU() with older binutils Commit a737737cdb9c ("s390/percpu: Infrastructure for more efficient this_cpu operations") introduced MVIY_PERCPU(), which stringifies arguments that are already C string literals. This generates an assembler macro invocation with whitespace-separated quoted arguments: GEN_MVIY "459712" "%r3" GNU as versions prior to binutils 2.39 drop the separating whitespace between quoted macro arguments during input scrubbing. They consequently parse the invocation as a single argument and emit repeated warnings: Warning: missing closing `"' The .ifc in GEN_MVIY never matches and GNU as exits successfully without emitting the mviy instruction. As a result, the interrupted per-CPU sequence is not marked in lowcore and the exception return path cannot repair the per-CPU address register after migration. All MVIY_PERCPU() callers pass C string literals. Use them directly and separate the assembler macro arguments with an explicit comma. The resulting invocation is: GEN_MVIY 459712, %r3 This form is unambiguous for GNU as and LLVM's integrated assembler. This behavior was fixed in GNU as from binutils 2.39, but Linux supports binutils 2.30.