netdev - Re: [PATCH bpf v2] bpftool: Don't crash on missing jited insns or ksyms

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Message-ID: <87eexbhopo.fsf@toke.dk>
Date:   Tue, 10 Dec 2019 22:09:55 +0100
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     Jakub Kicinski <jakub.kicinski@...ronome.com>
Cc:     Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <alexei.starovoitov@...il.com>,
        lkml <linux-kernel@...r.kernel.org>, netdev@...r.kernel.org,
        bpf@...r.kernel.org, Martin Lau <kafai@...com>
Subject: Re: [PATCH bpf v2] bpftool: Don't crash on missing jited insns or ksyms

Jakub Kicinski <jakub.kicinski@...ronome.com> writes:

> On Tue, 10 Dec 2019 19:14:12 +0100, Toke Høiland-Jørgensen wrote:
>> When the kptr_restrict sysctl is set, the kernel can fail to return
>> jited_ksyms or jited_prog_insns, but still have positive values in
>> nr_jited_ksyms and jited_prog_len. This causes bpftool to crash when trying
>> to dump the program because it only checks the len fields not the actual
>> pointers to the instructions and ksyms.
>> 
>> Fix this by adding the missing checks.
>> 
>> Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
>
> Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
>
> and
>
> Fixes: f84192ee00b7 ("tools: bpftool: resolve calls without using imm field")
>
> ?

Yeah, guess so? Although I must admit it's not quite clear to me whether
bpftool gets stable backports, or if it follows the "only moving
forward" credo of libbpf?

Anyhow, I don't suppose it'll hurt to have the Fixes: tag(s) in there;
does Patchwork pick these up (or can you guys do that when you apply
this?), or should I resend?

-Toke