netdev - Re: Assertion faileda at samples/bpf/test

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Message-ID: <CALDO+SYAxzzOTQu-Pgi6uPke0ojU46iS+0vk6cm5diytWca=EQ@mail.gmail.com>
Date:   Wed, 5 Oct 2016 09:48:52 +0900
From:   William Tu <u9012063@...il.com>
To:     Louie Lu <louie.lu@...ebaytech.com>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: Assertion faileda at samples/bpf/test_maps

Hi Louie,

Can you check whether your num_possible_cpu == num_online_cpu?
by doing:
cat /sys/devices/system/cpu/possible
and see how many cpu[0-9]
ls /sys/devices/system/cpu/cpu*

There is a related discussion here:
https://www.mail-archive.com/netdev@vger.kernel.org/msg121258.html

Regards,
William

On Sun, Oct 2, 2016 at 3:55 PM, Louie Lu <louie.lu@...ebaytech.com> wrote:
> Hi everyone,
>
> I'm now playing net-next samples/bpf things, and I found that
> test_maps will give an assertion
>
> ```
> test_maps: /home/grd/linux/net-next/samples/bpf/test_maps.c:146:
> test_percpu_hashmap_sanity: Assertion `bpf_lookup_elem(map_fd, &key,
> value) == -1 && errno == ENOENT' failed.
> [1]    20706 abort (core dumped)  ./test_maps
> ```
>
> I've done the check at [[iovisor-dev] Assertion fails at
> samples/bpf/test_maps](http://lists.iovisor.org/pipermail/iovisor-dev/2016-June/000281.html)
> which tells me to set ulimit to unlimited or patching by setrlimit().
>
> The problem is bpf_lookup_elem return -1, and errno return 0.
>
> I'm using Intel(R) Core(TM) i7-2640M and net-next commit:
> 803783849fed11, 4.8.0-rc7-ARCH-02283-g8037838.
>
> And, a strange this is when I done this at QEMU, test_maps perform
> will and pass the test.
>
> Is that my hardware problem or something else?
>
>
> Thanks.
>
> Louie Lu.