linux-kernel - Re: [PATCH bpf-next v2 2/2] selftests/bpf: Add test for BPF

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Message-ID: <3e3643bdbad74611b5c00bb2d5931647dc7b8208.camel@gmail.com>
Date: Mon, 27 Oct 2025 12:40:42 -0700
From: Eduard Zingerman <eddyz87@...il.com>
To: KaFai Wan <kafai.wan@...ux.dev>, ast@...nel.org, daniel@...earbox.net, 
	john.fastabend@...il.com, andrii@...nel.org, martin.lau@...ux.dev,
 song@...nel.org, 	yonghong.song@...ux.dev, kpsingh@...nel.org,
 sdf@...ichev.me, haoluo@...gle.com, 	jolsa@...nel.org, shuah@...nel.org,
 paul.chaignon@...il.com, m.shachnai@...il.com, 
	harishankar.vishwanathan@...il.com, colin.i.king@...il.com,
 luis.gerhorst@....de, 	bpf@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH bpf-next v2 2/2] selftests/bpf: Add test for BPF_JGT on
 same register

On Sat, 2025-10-25 at 13:30 +0800, KaFai Wan wrote:
> Add a test to verify that conditional jumps using the BPF_JGT opcode on
> the same register (e.g., "if r0 > r0") do not trigger verifier BUG
> warnings when the register contains a scalar value with range information.
> 
> Signed-off-by: KaFai Wan <kafai.wan@...ux.dev>
> ---

Could you please add test cases for JSET and for one of the *E
variants?

>  .../selftests/bpf/progs/verifier_bounds.c      | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/progs/verifier_bounds.c b/tools/testing/selftests/bpf/progs/verifier_bounds.c
> index 0a72e0228ea9..1536235c3e87 100644
> --- a/tools/testing/selftests/bpf/progs/verifier_bounds.c
> +++ b/tools/testing/selftests/bpf/progs/verifier_bounds.c
> @@ -1709,4 +1709,22 @@ __naked void jeq_disagreeing_tnums(void *ctx)
>  	: __clobber_all);
>  }
>  
> +SEC("socket")
> +__description("JGT on same register")
> +__success __log_level(2)
> +__retval(0)
> +__naked void jgt_same_register(void *ctx)
> +{
> +	asm volatile("			\
> +	call %[bpf_get_prandom_u32];	\
> +	w8 = 0x80000000;		\
> +	r0 &= r8;			\
> +	if r0 > r0 goto +1;		\
> +	r0 = 0;				\
> +	exit;				\
> +"	:
> +	: __imm(bpf_get_prandom_u32)
> +	: __clobber_all);
> +}
> +
>  char _license[] SEC("license") = "GPL";