Re: [PATCH v2] arm64: mops: Do not dereference src reg for a set operation

On Wed, 26 Mar 2025 11:04:47 +0000, Keir Fraser wrote:

The source register is not used for SET* and reading it can result in a UBSAN out-of-bounds array access error, specifically when the MOPS exception is taken from a SET* sequence with XZR (reg 31) as the source. Architecturally this is the only case where a src/dst/size field in the ESR can be reported as 31.

Prior to 2de451a329cf662b the code in do_el0_mops() was benign as the use of pt_regs_read_reg() prevented the out-of-bounds access.

[...]

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

[1/1] arm64: mops: Do not dereference src reg for a set operation https://git.kernel.org/arm64/c/a13bfa4fe0d6