[Bug 1876] New: high X nice value allows to crash the host

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https://bugs.freedesktop.org/show_bug.cgi?id=1876        
   
           Summary: high X nice value allows to crash the host
           Product: xorg
           Version: 6.7.0
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Server/general
        AssignedTo: xorg-bugzilla-noise at freedesktop.org
        ReportedBy: jerome.bouat at wanadoo.fr


On my Linux distribution, X nice value is 0. With such value, I already crashed
a host.

I got a program which made an eavy use of X by updating as quick as possible a
window (I did not designed it). X server spent all its time in managing the
memory instead of displaying. The more X server was loaded, the more it became
loaded up to the crash of the system.

Some malicious programs could exploit this feature in order to launch an attack
which causes a deny of service and then a system crash.

Choosing a -9 nice value fixes the problem in case where X client are on the
same host as X server. Indeed the X client waits for the load of the X server to
dicrease before it can get more resources.

For the case where the X client is not on the same host as the X server, I
assume the network link will limit the refresh rate.

Here is the bug report I posted on for my Linux distro:
http://qa.mandrakesoft.com/show_bug.cgi?id=8977        
   
   
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