Re: Assertion fails at samples/bpf/test_maps


Jesper Dangaard Brouer
 

On Wed, 22 Jun 2016 08:59:14 -0700
Alexei Starovoitov <alexei.starovoitov@...> wrote:

On Wed, Jun 22, 2016 at 8:54 AM, Jesper Dangaard Brouer
<brouer@...> wrote:
On Tue, 21 Jun 2016 18:54:53 -0700
Alexei Starovoitov <alexei.starovoitov@...> wrote:

On Tue, Jun 21, 2016 at 11:48 AM, William Tu via iovisor-dev
<iovisor-dev@...> wrote:
Hi,

I'm running test_maps under net-next/samples/bpf/, commit
601009780635. The code logic all make sense but I got the assertion
errors / coredump for some unknown reason under different compiler
optimization flags (-O0 and -O2). The test_hashmap_sanity() works fine
but fails at test_percpu_hashmap_sanity().

First run with normal build (which has -O2)
[root@vm-dev bpf]# ./test_maps
test_maps: samples/bpf/test_maps.c:137: test_percpu_hashmap_sanity:
Assertion `bpf_lookup_elem(map_fd, &key, value) == -1 &&
(*__errno_location ()) == 2' failed.
[...]

Strange I get:

$ sudo ./test_maps
failed to create per-cpu arraymap 'Operation not permitted'
yes. that's expected. Make sure to do 'ulimit -l unlimited'
# ulimit -l unlimited
# ./test_maps
test_maps: OK

Then it works, thanks. Maybe we could provide some better feedback from
the test program, as this might be a common/expected behavior.

--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer

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