netdev - Re: [PATCH v2 bpf-next 2/4] bpf: Teach the verifier to recognize rdonly

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Message-ID: <20230321222139.GB239208@maniforge>
Date:   Tue, 21 Mar 2023 17:21:39 -0500
From:   David Vernet <void@...ifault.com>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     davem@...emloft.net, daniel@...earbox.net, andrii@...nel.org,
        martin.lau@...nel.org, davemarchevsky@...a.com, tj@...nel.org,
        memxor@...il.com, netdev@...r.kernel.org, bpf@...r.kernel.org,
        kernel-team@...com
Subject: Re: [PATCH v2 bpf-next 2/4] bpf: Teach the verifier to recognize
 rdonly_mem as not null.

On Tue, Mar 21, 2023 at 01:38:52PM -0700, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@...nel.org>
> 
> Teach the verifier to recognize PTR_TO_MEM | MEM_RDONLY as not NULL
> otherwise if (!bpf_ksym_exists(known_kfunc)) doesn't go through
> dead code elimination.
> 
> Signed-off-by: Alexei Starovoitov <ast@...nel.org>

Acked-by: David Vernet <void@...ifault.com>