title: Can't access exe symlinks in centos 6.6 on docker
body: <p>I'm trying to access the /proc/&lt; pid >/exe symlink on centos 6.6 but i'm geting </p>
  
  <pre><code>ls: cannot access /proc/57/exe: Permission denied
  </code></pre>
  
  <p>My Dockerfile is </p>
  
  <pre><code>FROM centos:6
  
  # install base packages
  RUN yum -y update
  RUN yum -y groupinstall "Development Tools"
  RUN yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-    devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel
  RUN yum -y install wget
  RUN wget http://python.org/ftp/python/2.7.6/Python-2.7.6.tar.xz
  RUN yum -y install tar
  RUN tar -xf  Python-2.7.6.tar.xz
  
  RUN cd Python-2.7.6 &amp;&amp; ./configure --prefix=/usr/local --enable-unicode=ucs4 --enable-shared LDFLAGS="-Wl,-rpath /usr/local/lib"
  RUN cd Python-2.7.6 &amp;&amp; make
  RUN cd Python-2.7.6 &amp;&amp; make altinstall
  
  # First get the setup script for Setuptools:
  RUN wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py
  # Then install it for Python 2.7 and/or Python 3.3:
  RUN python2.7 ez_setup.py
  # Now install pip using the newly installed setuptools:
  RUN easy_install-2.7 pip
  
  #lxml
  RUN yum -y install python-devel libxml2-devel libxslt-devel
  RUN pip install lxml
  
  
  RUN pip install pytest
  RUN yum install -y gcc-c++
  RUN pip install protobuf
  RUN yum install -y rpm-build
  </code></pre>
  
  <p>This happens for any process.
  Thanks in advance.</p>