From: Ben Greear <greearb@candelatech.com>
To: David Ahern <dsahern@gmail.com>, netdev <netdev@vger.kernel.org>
Subject: Re: VRF and/or cgroups problem on Fedora-30, 5.2.21+ kernel
Date: Tue, 26 Nov 2019 09:36:57 -0800 [thread overview]
Message-ID: <5DDD62B9.3070909@candelatech.com> (raw)
In-Reply-To: <b64cb1b5-f9be-27ab-76e8-4fe84b947114@gmail.com>
On 11/25/2019 12:53 PM, David Ahern wrote:
> On 11/25/19 10:35 AM, Ben Greear wrote:
>>>> And surely 'ip' could output a better error than just 'permission
>>>> denied' for
>>>> this error case? Or even something that would show up in dmesg to give
>>>> a clue?
>>>
>>> That error comes from the bpf syscall:
>>>
>>> bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_CGROUP_SOCK, insn_cnt=6,
>>> insns=0x7ffc8e5d1e00, license="GPL", log_level=1, log_size=262144,
>>> log_buf="", kern_version=KERNEL_VERSION(0, 0, 0), prog_flags=0,
>>> prog_name="", prog_ifindex=0,
>>> expected_attach_type=BPF_CGROUP_INET_INGRESS, prog_btf_fd=0,
>>> func_info_rec_size=0, func_info=NULL, func_info_cnt=0,
>>> line_info_rec_size=0, line_info=NULL, line_info_cnt=0}, 112) = -1 EPERM
>>> (Operation not permitted)
>>
>> So, we can change iproute/lib/bpf.c to print a suggestion to increase
>> locked memory
>> if this returns EPERM?
>>
>
> looks like SYS_ADMIN and locked memory are the -EPERM failures.
>
> I do not see any API that returns user->locked_vm, only per-task
> locked_vm. Knowing that number would help a lot in understanding proper
> system settings.
>
> Running 'perf record' while trying to do 'ip vrf exec' is an easy way to
> hit the locked memory exceeded error. We could add a hint to iproute2.
> Something like:
>
> diff --git a/ip/ipvrf.c b/ip/ipvrf.c
> index b9a43675cbd6..15637924f31a 100644
> --- a/ip/ipvrf.c
> +++ b/ip/ipvrf.c
> @@ -281,9 +281,16 @@ static int vrf_configure_cgroup(const char *path,
> int ifindex)
> fprintf(stderr, "Failed to load BPF prog: '%s'\n",
> strerror(errno));
>
> - if (errno != EPERM) {
> + if (errno == EPERM) {
> + if (geteuid() != 0)
> + fprintf(stderr,
> + "Hint: Must run as root to set
> VRF.\n");
> + else
> + fprintf(stderr,
> + "Hint: Most likely locked memory
> threshold exceeded. Increase 'ulimit -l'\n");
I think I would suggest 'ulimit -l 1024'. Advanced users can try different
values if they care or have super tight memory constraints, but most users could
probably get benefit from the suggestion.
Thanks,
Ben
> + } else {
> fprintf(stderr,
> - "Kernel compiled with CGROUP_BPF
> enabled?\n");
> + "Hint: Kernel compiled with CGROUP_BPF
> enabled?\n");
> }
> goto out;
> }
>
--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
prev parent reply other threads:[~2019-11-26 17:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-23 0:03 VRF and/or cgroups problem on Fedora-30, 5.2.21+ kernel Ben Greear
2019-11-23 0:06 ` David Ahern
2019-11-23 0:14 ` Ben Greear
2019-11-23 0:17 ` David Ahern
2019-11-23 0:23 ` Ben Greear
2019-11-23 18:10 ` David Ahern
2019-11-25 17:35 ` Ben Greear
2019-11-25 20:53 ` David Ahern
2019-11-26 8:48 ` Toke Høiland-Jørgensen
2019-11-26 17:36 ` Ben Greear [this message]
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