Re: [PATCH nf] nft_set_pipapo_avx2: Add irq_fpu_usable() check, fallback to non-AVX2 version

On Mon, May 10, 2021 at 07:58:22AM +0200, Stefano Brivio wrote:

Arturo reported this backtrace:

[709732.358791] WARNING: CPU: 3 PID: 456 at arch/x86/kernel/fpu/core.c:128 kernel_fpu_begin_mask+0xae/0xe0

[...]

that is, nft_pipapo_avx2_lookup() uses the FPU running from a softirq that interrupted a kthread, also using the FPU.

That's exactly the reason why irq_fpu_usable() is there: use it, and if we can't use the FPU, fall back to the non-AVX2 version of the lookup operation, i.e. nft_pipapo_lookup().

Applied to nf, thanks.