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From: Yonghong Song <yonghong.song@linux.dev>
To: Eduard Zingerman <eddyz87@gmail.com>, bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	kernel-team@fb.com
Subject: Re: [PATCH bpf-next 06/12] bpf: Force JIT for programs using the R0:R2 register pair
Date: Thu, 9 Jul 2026 22:09:27 -0700	[thread overview]
Message-ID: <72cf9c2a-cafa-46c1-8746-9a8b53e5c1c7@linux.dev> (raw)
In-Reply-To: <cdff0944003193d4224a1fec5f1fb9fa8bd76801.camel@gmail.com>



On 7/9/26 3:27 PM, Eduard Zingerman wrote:
> On Wed, 2026-07-08 at 13:10 -0700, Yonghong Song wrote:
>
> [...]
>
>> @@ -9877,7 +9886,7 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
>>   	} else {
>>   		/* return to the caller whatever r0 had in the callee */
>>   		caller->regs[BPF_REG_0] = *r0;
>> -		if (bpf_ret_reg_pair(env, callee->subprogno)) {
>> +		if (bpf_ret_reg_pair_mark(env, callee->subprogno)) {
> Also, doing this while processing exit is a bit strange.
> I think this should be done in do_check_common().

Before sending this patch, I found two places to do this, prepare_func_exit() and
do_check_common(). Since you mentioned, I will do do_check_common() then.

>
>>   			if (callee->regs[BPF_REG_2].type == PTR_TO_STACK) {
>>   				verbose(env, "cannot return stack pointer to the caller\n");
>>   				return -EINVAL;
> [...]


  reply	other threads:[~2026-07-10  5:09 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-08 20:09 [PATCH bpf-next 00/12] bpf: Support 16-byte return values in the R0:R2 register pair Yonghong Song
2026-07-08 20:09 ` [PATCH bpf-next 01/12] bpf: Factor check_global_ret_scalar_reg() out of the global return check Yonghong Song
2026-07-08 20:09 ` [PATCH bpf-next 02/12] bpf: Add verifier support for 16-byte returns in R0:R2 Yonghong Song
2026-07-08 21:17   ` bot+bpf-ci
2026-07-09 16:40     ` Yonghong Song
2026-07-09 22:21   ` Eduard Zingerman
2026-07-10  4:57     ` Yonghong Song
2026-07-08 20:09 ` [PATCH bpf-next 03/12] bpf: Wire up JIT support for 16-byte kfunc returns Yonghong Song
2026-07-10  0:06   ` Eduard Zingerman
2026-07-08 20:10 ` [PATCH bpf-next 04/12] bpf: Track R2 of register-pair returns in precision backtracking Yonghong Song
2026-07-08 21:10   ` bot+bpf-ci
2026-07-09 16:41     ` Yonghong Song
2026-07-10  0:31   ` Eduard Zingerman
2026-07-08 20:10 ` [PATCH bpf-next 05/12] bpf: Account R2 of register-pair returns in live register analysis Yonghong Song
2026-07-08 21:10   ` bot+bpf-ci
2026-07-09 21:07   ` Eduard Zingerman
2026-07-10  5:06     ` Yonghong Song
2026-07-08 20:10 ` [PATCH bpf-next 06/12] bpf: Force JIT for programs using the R0:R2 register pair Yonghong Song
2026-07-08 21:10   ` bot+bpf-ci
2026-07-09  3:15   ` Leon Hwang
2026-07-09 16:44     ` Yonghong Song
2026-07-09 20:30   ` Eduard Zingerman
2026-07-10  5:07     ` Yonghong Song
2026-07-09 22:27   ` Eduard Zingerman
2026-07-10  5:09     ` Yonghong Song [this message]
2026-07-08 20:10 ` [PATCH bpf-next 07/12] bpf: Reject >8 byte return values on return-reading trampoline paths Yonghong Song
2026-07-09  3:16   ` Leon Hwang
2026-07-09 16:52     ` Yonghong Song
2026-07-10  2:01       ` Leon Hwang
2026-07-09 23:08   ` Eduard Zingerman
2026-07-10  2:02     ` Leon Hwang
2026-07-10  5:27       ` Yonghong Song
2026-07-10  5:12     ` Yonghong Song
2026-07-08 20:10 ` [PATCH bpf-next 08/12] bpf: Enable 16-byte aggregate return types Yonghong Song
2026-07-08 20:28   ` sashiko-bot
2026-07-09 19:40     ` Yonghong Song
2026-07-10  0:45   ` Eduard Zingerman
2026-07-10  5:29     ` Yonghong Song
2026-07-08 20:10 ` [PATCH bpf-next 09/12] selftests/bpf: Add C tests for 16-byte returns in R0:R2 Yonghong Song
2026-07-08 20:24   ` sashiko-bot
2026-07-09 19:51     ` Yonghong Song
2026-07-08 21:10   ` bot+bpf-ci
2026-07-09 19:54     ` Yonghong Song
2026-07-10  1:19   ` Eduard Zingerman
2026-07-10  5:32     ` Yonghong Song
2026-07-08 20:10 ` [PATCH bpf-next 10/12] selftests/bpf: Add inline-asm and subprog tests for R0:R2 returns Yonghong Song
2026-07-08 20:28   ` sashiko-bot
2026-07-09 19:57     ` Yonghong Song
2026-07-10  1:38   ` Eduard Zingerman
2026-07-10  5:35     ` Yonghong Song
2026-07-08 20:10 ` [PATCH bpf-next 11/12] selftests/bpf: Cover tracing on >8 and <=16 byte return targets Yonghong Song
2026-07-08 20:10 ` [PATCH bpf-next 12/12] Documentation/bpf: Document 16-byte kfunc return values in R0:R2 Yonghong Song
2026-07-10  0:56 ` [PATCH bpf-next 00/12] bpf: Support 16-byte return values in the R0:R2 register pair Eduard Zingerman
2026-07-10  6:00   ` Yonghong Song
2026-07-10  6:13     ` Eduard Zingerman
2026-07-10 15:18       ` Yonghong Song

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