[PATCH] arm64/fpsimd: signal: Forbid non-streaming SVE payload on SME-only systems

[Will Deacon]

On Thu, 01 Oct 2026 14:08:36 +0100, Mark Rutland wrote:
> When system_supports_sme() is true but system_supports_sve() is false,
> restoring a specifically crafted SVE signal context can result in the
> task erroneously having non-streaming SVE state. Subsequent attempts to
> manipulate the task's FPSIMD/SVE/SME state can result in a variety of
> problems, including fatal EL1 UNDEFs.
> 
> In such configurations, the kernel always creates an SVE signal context
> when delivering a signal, and this can only be in one of two states:
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64/fpsimd: signal: Forbid non-streaming SVE payload on SME-only systems
      https://git.kernel.org/arm64/c/e060d9069b49

Cheers,
-- 
Will

https://fixes.arm64.dev
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