[LTP] [PATCH v4 0/4] New Fuzzy Sync library API

Li Wang liwang@redhat.com
Fri Nov 16 15:33:44 CET 2018

On Mon, Nov 5, 2018 at 11:42 PM, Richard Palethorpe
<rpalethorpe@suse.com> wrote:
> Changes for V4:
> * Increase fzsync timeout to 50% of the overall LTP test timeout
> * Increase default iterations to 3 million
> * Set cve-2014-0196 iterations to 50,000
> * Increase sample iterations for cve-2016-7117
> With these defaults almost all of the tests should reliably trigger their
> bugs while not taking more than 30 seconds to execute on server grade
> hardware. On slow embedded systems the tests should also be fairly reliable,
> however will take up to 150 seconds.
> Hopefully none of the tests will exit with a warning on slow systems because
> they failed to complete the sampling phase. However on a very slow system
> cve-2016-7117 will probably not have time to finish the sampling phase, but
> this bug is simply very difficult to reproduce[1] on some kernels and a long
> sampling time is required to get the optimal delay bias.

I run these corresponding tests[1] with applying the new fuzzy_sync
API on some slow systems. The follows are the test status and sampling
time consumption.

1. KVM Guest, RHEL-7.6GA, x86_64, 1vcpu, 1G RAM
cve-2016-7117 and shmctl05 failed to complete the sampling phase and
eventually exit with warnings.

Sampling time consume:
cve-2016-7117: ~440.31s
cve-2014-0196: ~33.77s
cve-2017-2671: ~33.81s
inotify09: ~33.83s
shmctl05: ~33.78s
test16: ~44.91s

My extra proposal for test shmctl05 is to extend its timeout from 20s
to 100s. Because from the time cost detection on such a slow(1cpu, 1G
ram) machine, 10s(1/2 of .timeout=20) is too short to finish sampling.

2. KVM Guest, RHEL-7.6GA, x86_64, 2vcpu, 2G RAM
All test[1] PASS with execution time/loops exceeded. I didn't do time
consume detection on this system.

3. Raspberry Pi3, CentOS-7.5(4.14.78-v7.1.el7 armv7l), 4cpus, 1G RAM
All test[1] PASS with execution time/loops exceeded.
What surprised me was that the average of sampling time is only 9~11
seconds on the RaspbeeryPi3. Even includes cve-2016-7117 also complete
its sampling phase so fast!

[1] cve-2014-0196 cve-2016-7117 cve-2017-2671 inotify09 shmctl05 test16

Li Wang

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