Re: [PATCH 2/2] riscv, bpf: use lw when reading int cpu in bpf_get_smp_processor_id

[Pu Lehui]

On 2025/8/12 17:02, Radim Krčmář wrote:
> emit_ld is wrong, because thread_info.cpu is 32-bit, not xlen-bit wide.
> The struct currently has a hole after cpu, so little endian accesses
> seemed fine.
>
> Fixes: 2ddec2c80b44 ("riscv, bpf: inline bpf_get_smp_processor_id()")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxxxxxxxx>
> ---
>   arch/riscv/net/bpf_jit_comp64.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
> index 6e1554d89681..9883a55d61b5 100644
> --- a/arch/riscv/net/bpf_jit_comp64.c
> +++ b/arch/riscv/net/bpf_jit_comp64.c
> @@ -1763,7 +1763,7 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
>   		 */
>   		if (insn->src_reg == 0 && insn->imm == BPF_FUNC_get_smp_processor_id) {
>   			/* Load current CPU number in R0 */
> -			emit_ld(bpf_to_rv_reg(BPF_REG_0, ctx), offsetof(struct thread_info, cpu),
> +			emit_lw(bpf_to_rv_reg(BPF_REG_0, ctx), offsetof(struct thread_info, cpu),
>   				RV_REG_TP, ctx);
>   			break;
>   		}

Reviewed-by: Pu Lehui <pulehui@xxxxxxxxxx>