Re: [chrony-dev] crash when overloading refclock_sock

[Nuno Gonçalves <nunojpg@xxxxxxxxx>]

Hi,

Still crashes:

2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
63 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
0 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
1 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
2 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
3 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
4 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
5 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
6 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
7 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
8 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
9 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
10 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
11 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
12 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
13 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
14 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
15 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
16 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
17 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
18 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
19 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z refclock.c:713:(filter_add_sample) filter sample
20 t=1475822340.876999761 offset=0.123000145 dispersion=0.000000001
2016-10-07T06:39:01Z sources.c:360:(SRC_AccumulateSample) ip=[SOCK]
t=1475822340.876999761 ofs=-0.123000 del=0.000000 disp=-nan str=0
2016-10-07T06:39:01Z sourcestats.c:550:(SST_DoNewRegression) off=-nan
freq=-nan skew=-nan n=3 bs=0 runs=3 asym=0.000000 arun=0
chronyd: sourcestats.c:388: find_best_sample_index: Assertion
`best_index >= 0' failed.
Aborted (core dumped)

Thanks,
Nuno

On Thu, Oct 6, 2016 at 4:20 PM, Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:
> On Wed, Oct 05, 2016 at 10:56:04AM +0200, Nuno Gonçalves wrote:
>> I was testing a refclock_sock provider and when the rate of messages
>> is really high (over 50k/s), I manage to crash chronyd.
>>
>> Yes, this is not the standard use case, usually I publish 1/s, but
>> anyway chrony ideally should resist to this abuse.
>>
>>
>> 2016-10-05T07:58:01Z refclock.c:707:(filter_add_sample) filter sample
>> 52 t=1475654280.876999978 offset=0.122999928 dispersion=0.000000001
>> 2016-10-05T07:58:01Z refclock.c:707:(filter_add_sample) filter sample
>> 53 t=1475654280.876999978 offset=0.122999928 dispersion=0.000000001
>> 2016-10-05T07:58:01Z refclock.c:707:(filter_add_sample) filter sample
>> 54 t=1475654280.876999978 offset=0.122999928 dispersion=0.000000001
>> 2016-10-05T07:58:01Z refclock.c:707:(filter_add_sample) filter sample
>> 55 t=1475654280.876999978 offset=0.122999928 dispersion=0.000000001
>> 2016-10-05T07:58:01Z sources.c:360:(SRC_AccumulateSample) ip=[SOCK]
>> t=1475654280.876999978 ofs=-0.123000 del=0.000000 disp=-nan str=0
>> chronyd: sourcestats.c:388: find_best_sample_index: Assertion
>> `best_index >= 0' failed.
>> Aborted (core dumped)
>
> Thanks for the bug report. It looks like the problem is that there are
> multiple samples with the same local timestamp, which breaks the
> calculation of the dispersion.
>
> Can you please pull from git and see if it's fixed?
>
> --
> Miroslav Lichvar
>
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