SIGSEGV in syslog driver

[matevarga]

• This is a bug report
• This is a feature request
• I searched existing issues before opening this one

Expected behavior

Docker daemon works properly.

Actual behavior

Docker daemon crashed:
/var/log/upstart/docker.log

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x1512ea2]

goroutine 824906 [running]:
github.com/docker/docker/daemon/logger/syslog.(*syslogger).Log(0xc42000e520, 0xc422886360, 0x0, 0x0)
        /go/src/github.com/docker/docker/daemon/logger/syslog/syslog.go:137 +0x82
github.com/docker/docker/daemon/logger.(*RingLogger).run(0xc422d2ab40)
        /go/src/github.com/docker/docker/daemon/logger/ring.go:116 +0x7c
created by github.com/docker/docker/daemon/logger.newRingLogger
        /go/src/github.com/docker/docker/daemon/logger/ring.go:43 +0x207

Steps to reproduce the behavior

I can't reproduce this, it was a crash in production. There's been no memory pressure or high load on the server.

Output of docker version:

Docker version 17.06.0-ce, build 02c1d87

Output of docker info:

Containers: 11
 Running: 9
 Paused: 0
 Stopped: 2
Images: 44
Server Version: 17.06.0-ce
Storage Driver: aufs
 Root Dir: # redacted #
 Backing Filesystem: extfs
 Dirs: 604
 Dirperm1 Supported: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay weavemesh
 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: cfb82a876ecc11b5ca0977d1733adbe58599088a
runc version: 2d41c047c83e09a6d61d464906feb2a2f3c52aa4
init version: 949e6fa
Security Options:
 apparmor
Kernel Version: 4.4.0-75-generic
Operating System: Ubuntu 14.04.5 LTS
OSType: linux
Architecture: x86_64
CPUs: 16
Total Memory: 62.92GiB
Name: # redacted # 
ID: 7JF5:X2H4:IMXS:Y6RK:IL74:RZ3B:LP4C:YOSL:PT2H:OGQS:L33G:QDNS
Docker Root Dir: # redacted #
Debug Mode (client): false
Debug Mode (server): false
Http Proxy: # redacted #
Https Proxy: # redacted #
Username: # redacted #
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false

WARNING: No swap limit support

Additional environment details (AWS, VirtualBox, physical, etc.)

VMWare ESXi, DOCKER_OPTS="--storage-driver=aufs --log-opt mode=non-blocking"

[thaJeztah]

This looks like a duplicate of moby/moby#34869, which was resolved in moby/moby#33832 (back ported to Docker CE 17.06.1 and up through docker-archive/docker-ce#95

I recommend updating to 17.06.2. Be aware that Docker 17.06.x has reached end of life; the current "stable" release of Docker CE is 17.09, which is still supported.

I'll go ahead and close this, because this should be fixed, but leave a comment if you're still able to reproduce after updating, thanks!

[matevarga]

Cheers.