From: Yonghong Song <yhs@fb.com>
To: "Daniel Borkmann" <daniel@iogearbox.net>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
ast@fb.com
Cc: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf] libbpf: Sanitise internal map names so they are not rejected by the kernel
Date: Tue, 18 Feb 2020 08:19:05 -0800 [thread overview]
Message-ID: <a0923745-ee34-3eb0-7f9b-31cec99661ec@fb.com> (raw)
In-Reply-To: <9ddddbd6-aca2-61ae-b864-0f12d7fd33b4@iogearbox.net>
On 2/18/20 6:40 AM, Daniel Borkmann wrote:
> On 2/17/20 6:17 PM, Toke Høiland-Jørgensen wrote:
>> The kernel only accepts map names with alphanumeric characters,
>> underscores
>> and periods in their name. However, the auto-generated internal map names
>> used by libbpf takes their prefix from the user-supplied BPF object name,
>> which has no such restriction. This can lead to "Invalid argument" errors
>> when trying to load a BPF program using global variables.
>>
>> Fix this by sanitising the map names, replacing any non-allowed
>> characters
>> with underscores.
>>
>> Fixes: d859900c4c56 ("bpf, libbpf: support global data/bss/rodata
>> sections")
>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>
> Makes sense to me, applied, thanks! I presume you had something like '-'
> in the
> global var leading to rejection?
The C global variable cannot have '-'. I saw a complain in bcc mailing
list sometimes back like: if an object file is a-b.o, then we will
generate a map name like a-b.bss for the bss ELF section data. The
map name "a-b.bss" name will be rejected by the kernel. The workaround
is to change object file name. Not sure whether this is the only
issue which may introduce non [a-zA-Z0-9_] or not. But this patch indeed
should fix the issue I just described.
next prev parent reply other threads:[~2020-02-18 16:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-17 17:17 [PATCH bpf] libbpf: Sanitise internal map names so they are not rejected by the kernel Toke Høiland-Jørgensen
2020-02-18 14:40 ` Daniel Borkmann
2020-02-18 16:19 ` Yonghong Song [this message]
2020-02-18 16:42 ` Toke Høiland-Jørgensen
2020-02-18 22:54 ` Daniel Borkmann
2020-02-19 10:28 ` Toke Høiland-Jørgensen
2020-02-19 16:45 ` Yonghong Song
2020-02-19 22:29 ` Toke Høiland-Jørgensen
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