**Reported in Launchpad by David Busby last update 30-10-2013 12:34:57

PS 56-5.6.14-rel62

Line 773 -> 774 of mysqld_safe:

"""

1. Purge page cache, dentires and inodes.
   elif ! sysctl -q-w vm.drop_caches=3
   """

This also leads (rightly so) to an selinux denial (tested on Fedora19):

—
Additional Information:
Source Context unconfined_u:system_r:mysqld_safe_t:s0
Target Context system_u:object_r:sysctl_vm_t:s0
Target Objects /proc/sys/vm/drop_caches [ file ]
Source sysctl
Source Path /usr/sbin/sysctl
Port <Unknown>
Host phobetor-oneiroi-co-uk
Source RPM Packages procps-ng-3.3.8-10.fc19.x86_64
Target RPM Packages
Policy RPM selinux-policy-3.12.1-74.10.fc19.noarch
Selinux Enabled True
Policy Type targeted
Enforcing Mode Enforcing
Host Name phobetor-oneiroi-co-uk
Platform Linux phobetor-oneiroi-co-uk
3.11.6-200.fc19.x86_64 #1 SMP Fri Oct 18 22:34:18
UTC 2013 x86_64 x86_64
Alert Count 16
First Seen 2013-10-19 14:02:02 BST
Last Seen 2013-10-30 12:16:19 GMT
Local ID aee4f2c2-c57f-4da3-a9f8-659768f9a645

Raw Audit Messages
type=AVC msg=audit(1383135379.894:520): avc: denied { getattr } for pid=3675 comm="sysctl" path="/proc/sys/vm/drop_caches" dev="proc" ino=21262 scontext=unconfined_u:system_r:mysqld_safe_t:s0 tcontext=system_u:object_r:sysctl_vm_t:s0 tclass=file

type=SYSCALL msg=audit(1383135379.894:520): arch=x86_64 syscall=stat success=no exit=EACCES a0=2312080 a1=7ffff3a2b290 a2=7ffff3a2b290 a3=3580531fd0 items=0 ppid=3040 pid=3675 auid=1000 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 ses=2 tty=(none) comm=sysctl exe=/usr/sbin/sysctl subj=unconfined_u:system_r:mysqld_safe_t:s0 key=(null)

Hash: sysctl,mysqld_safe_t,sysctl_vm_t,file,getattr
—

Surely we should not be dropping system wide caches on a mysql startup for production systems? we have no way of knowing if PS is being deployed onto a dedicated system; dropping caches on a shared system could lead issues.