s390/percpu: Fix MVIY_PERCPU() with older binutils

Summary

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.

Timeline

1. Sep 11, 2026, 7:43 PM UTCCVE published
2. Oct 19, 2026, 8:47 AM UTCRecord last updated

Affected versions

• Linux Linux

  From a737737cdb9c94e40a9926cdc2320f874c05d709 · fixed in 91770b08a120967077ae78600612f18bc5ee3caf; From a737737cdb9c94e40a9926cdc2320f874c05d709 · fixed in 101782f8945a125044347312d74d488c05741c4a

• Linux Linux

  7.2

• KernelLinux

  From 7.2.0 · fixed in 7.2.4

References 2