From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Ihor Solodrai" <ihor.solodrai@linux.dev>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Kumar Kartikeya Dwivedi" <memxor@gmail.com>
Cc: "Amery Hung" <ameryhung@gmail.com>,
"Emil Tsalapatis" <emil@etsalapatis.com>,
"Nicholas Carlini" <npc@anthropic.com>, <bpf@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <kernel-team@meta.com>
Subject: Re: [PATCH bpf-next v1 0/6] bpf: Scope callback arguments to their frame
Date: Tue, 22 Sep 2026 01:55:06 +0000 [thread overview]
Message-ID: <DLLGYV7DI406.JRNDNAZ4S29I@gmail.com> (raw)
In-Reply-To: <20260922010333.1226537-1-ihor.solodrai@linux.dev>
On Mon, Sep 21, 2026 at 06:03 PM Ihor Solodrai <ihor.solodrai@linux.dev> wrote:
> Neither has a local fix: both arguments point into a helper's own
> frame, with nothing longer-lived to anchor them to.
It's the same problem as a pointer to callee's stack.
check_stack_write_fixed_off() deals with it like this:
if (state != cur && reg->type == PTR_TO_STACK) {
verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
return -EINVAL;
}
CONST_PTR_TO_DYNPTR wasn't spillable before 7.3, so nothing depends
on parking it in the caller's frame. Reject it there too ?
and then no need for REF_TYPE_FRAME complexity?
next prev parent reply other threads:[~2026-09-22 1:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 1:03 Ihor Solodrai
2026-09-22 1:03 ` [PATCH bpf-next v1 1/6] bpf: Introduce REF_TYPE_FRAME in the verifier Ihor Solodrai
2026-09-22 2:01 ` bot+bpf-ci
2026-09-22 1:03 ` [PATCH bpf-next v1 2/6] bpf: Scope the bpf_user_ringbuf_drain() dynptr to its callback frame Ihor Solodrai
2026-09-22 1:47 ` bot+bpf-ci
2026-09-22 1:03 ` [PATCH bpf-next v1 3/6] bpf: Name the callback in frame-release diagnostics Ihor Solodrai
2026-09-22 1:03 ` [PATCH bpf-next v1 4/6] selftests/bpf: Cover the user ringbuf callback dynptr lifetime Ihor Solodrai
2026-09-22 1:47 ` bot+bpf-ci
2026-09-22 1:03 ` [PATCH bpf-next v1 5/6] bpf: Scope the bpf_for_each_map_elem() array key to the callback frame Ihor Solodrai
2026-09-22 1:03 ` [PATCH bpf-next v1 6/6] selftests/bpf: Cover callback-frame map key lifetime Ihor Solodrai
2026-09-22 1:47 ` bot+bpf-ci
2026-09-22 1:55 ` Alexei Starovoitov [this message]
2026-09-22 2:15 ` [PATCH bpf-next v1 0/6] bpf: Scope callback arguments to their frame Kumar Kartikeya Dwivedi
2026-09-22 6:13 ` Ihor Solodrai
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