[MOD] fix fatal error: concurrent map read and map write

[cmingxu]

No description provided.

[GordonTheTurtle]

Please sign your commits following these rules:
https://github.com/docker/docker/blob/master/CONTRIBUTING.md#sign-your-work
The easiest way to do this is to amend the last commit:

$ git clone -b "master" git@github.com:cmingxu/libnetwork.git somewhere
$ cd somewhere
$ git commit --amend -s --no-edit
$ git push -f

Amending updates the existing PR. You DO NOT need to open a new one.

[kalahari]

I believe I am experiencing the issue solved in this pull, would it be of any use for me to open an issue?

...
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: time="2016-10-20T02:35:07-05:00" level=info msg="Firewalld running: false"
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: time="2016-10-20T02:35:07.261788623-05:00" level=info msg="Failed to delete real server 172.30.100.99 for vip 172.30.100.13 fwmark 330: no such process"
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: fatal error: concurrent map read and map write
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: goroutine 4061103 [running]:
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: runtime.throw(0x1f57880, 0x21)
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: /usr/local/go/src/runtime/panic.go:547 +0x90 fp=0xc82a590ca0 sp=0xc82a590c88
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: runtime.mapaccess2_faststr(0x16f7600, 0xc830803710, 0xc82cf00b40, 0x40, 0xc82030a000, 0xc82933dcc0)
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: /usr/local/go/src/runtime/hashmap_fast.go:307 +0x5b fp=0xc82a590d00 sp=0xc82a590ca0
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: github.com/docker/libnetwork.(*sandbox).isEndpointPopulated(0xc82dd1a780, 0xc827540dc0, 0x1)
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: /root/rpmbuild/BUILD/docker-engine/vendor/src/github.com/docker/libnetwork/sandbox.go:972 +0x85 fp=0xc82a590d50 sp=0xc82a590d00
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: github.com/docker/libnetwork.(*network).rmLBBackend.func1(0x7fdb9c0bf128, 0xc827540dc0, 0x0)
Oct 20 02:35:07 d9-t29-lsmo01.clarabridge.net dockerd[11172]: /root/rpmbuild/BUILD/docker-engine/vendor/src/github.com/docker/libnetwork/service_linux.go:350 +0xd1 fp=0xc82a590e38 sp=0xc82a590d50
...

[mrjana]

@kalahari There is already an issue moby/moby#27486 and it is already fixed. It will be available in the next patch release.

[aboch]

This change does not fix the original issue.
The fix for it was pushed in #1512 and merged.

[aboch]

The access to this map is already protected by sandbox lock.
This change does not help.

The root cause of the issue was a delete on the map run outside of sandbox lock and was fixed in #1512

[aboch]

You adding sync.RWMutex along with the existing sync.Mutex.
From which package will all the existing calls sb.Lock()/Unlock() execute, sync.mutex or sync.RWMutex ?
If we were to accept this change, you should remove sync.Mutex.

[aboch]

Based on the comments, I will go ahead and close this PR