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Message-ID: <de6b04bdb2627a7decfd6b6c98c1093631a6a87b.camel@gmail.com>
Subject: Re: [PATCH RFC bpf-next v3 06/16] bpf/helpers: introduce
 bpf_timer_set_sleepable_cb() kfunc
From: Eduard Zingerman <eddyz87@gmail.com>
To: Benjamin Tissoires <bentiss@kernel.org>, Alexei Starovoitov
 <ast@kernel.org>,  Daniel Borkmann <daniel@iogearbox.net>, John Fastabend
 <john.fastabend@gmail.com>, Andrii Nakryiko <andrii@kernel.org>, Martin
 KaFai Lau <martin.lau@linux.dev>, Song Liu <song@kernel.org>, Yonghong Song
 <yonghong.song@linux.dev>, KP Singh <kpsingh@kernel.org>, Stanislav
 Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>, Jiri Olsa
 <jolsa@kernel.org>, Jiri Kosina <jikos@kernel.org>,  Benjamin Tissoires
 <benjamin.tissoires@redhat.com>, Jonathan Corbet <corbet@lwn.net>, Shuah
 Khan <shuah@kernel.org>
Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-input@vger.kernel.org, linux-doc@vger.kernel.org, 
	linux-kselftest@vger.kernel.org
Date: Fri, 23 Feb 2024 17:10:52 +0200
In-Reply-To: <20240221-hid-bpf-sleepable-v3-6-1fb378ca6301@kernel.org>
References: <20240221-hid-bpf-sleepable-v3-0-1fb378ca6301@kernel.org>
	 <20240221-hid-bpf-sleepable-v3-6-1fb378ca6301@kernel.org>
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On Wed, 2024-02-21 at 17:25 +0100, Benjamin Tissoires wrote:

[...]

> @@ -12120,6 +12137,16 @@ static int check_kfunc_call(struct bpf_verifier_=
env *env, struct bpf_insn *insn,
>  		}
>  	}
> =20
> +	if (is_async_callback_calling_kfunc(meta.func_id)) {

I think that it's better to check specific kfunc id here:

  meta.func_id =3D=3D special_kfunc_list[KF_bpf_timer_set_sleepable_cb_impl=
]

In case if some new async callback calling kfunc would be added,
for which set_timer_callback_state() won't be correct.

> +		err =3D push_callback_call(env, insn, insn_idx, meta.subprogno,
> +					 set_timer_callback_state);
> +		if (err) {
> +			verbose(env, "kfunc %s#%d failed callback verification\n",
> +				func_name, meta.func_id);
> +			return err;
> +		}
> +	}
> +
>  	rcu_lock =3D is_kfunc_bpf_rcu_read_lock(&meta);
>  	rcu_unlock =3D is_kfunc_bpf_rcu_read_unlock(&meta);
> =20
>=20