[Bug 1087700] New: lost signals when sending lots of signals using --sig-proxy to docker

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1087700

Bug ID: 1087700
           Summary: lost signals when sending lots of signals using
                    --sig-proxy to docker
           Product: Fedora
           Version: 20
         Component: docker-io
          Assignee: [e-mail]
          Reporter: [e-mail]
        QA Contact: [e-mail]
                CC: [e-mail], [e-mail],
                    [e-mail], [e-mail],
                    [e-mail], [e-mail],
                    [e-mail]

Description of problem:
When I send lots of signals to the running docker with --sig-proxy (actual kill
signals, not `docker kill`), most of them got lost.

Version-Release number of selected component (if applicable):
docker-io-0.9.1-1.fc21.x86_64

How reproducible:
always

Steps to Reproduce:
1. /usr/bin/docker -D run --tty=false --rm -i --name test_eoly
localhost:5000/ldoktor/fedora:latest bash -c 'for NUM in `seq 1 64`; do trap
"echo Received $NUM, ignoring..." $NUM; done; while :; do sleep 1; done'
2. ps ax |grep docker
3. for AAA in `seq 1 32`; do [ $AAA -ne 9 ] && [ $AAA -ne 20 ] && [ $AAA -ne 19
] && kill -s $AAA $PID; done

Actual results:
Output of the docker is:
Received 1, ignoring...
Received 2, ignoring...

Expected results:
Messages for all of the `Received $NUM, ignoring...` printed (order doesn't
matter)

Additional info:
Skipping 9, 19, 20 as they are a bit too special..