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Bug 470525

Summary: Kernels 2.6.9-78+ create an unexpected /proc/xen directory
Product: Red Hat Enterprise Linux 4 Reporter: Trevor Hemsley <trevor.hemsley>
Component: kernel-xenAssignee: Don Dutile (Red Hat) <ddutile>
Status: CLOSED DUPLICATE QA Contact: Martin Jenner <mjenner>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.7CC: xen-maint
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2008-11-11 15:46:32 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description Trevor Hemsley 2008-11-07 15:20:28 UTC
Description of problem:
All kernels since 2.6.9-78 create a /proc/xen directory containing the 'file' 'balloon'. This is true on non-Xen kernels and running without any sort of virtualization product installed or running.

Version-Release number of selected component (if applicable):
kernel-2.6.9-78.EL (and 2.6.9-78.0.1 through 5) and affects smp kernels as well


How reproducible:
Every time

Steps to Reproduce:
1. Install any RH kernel newer than 2.6.9-78
2. Boot it
3. ls -la /proc/xen
  
Actual results:
total 0
dr-xr-xr-x    2 root root 0 Nov  7 15:16 .
dr-xr-xr-x  304 root root 0 Aug 28 21:11 ..
-rw-r--r--    1 root root 0 Nov  7 15:16 balloon

Expected results:
ls: /proc/xen: No such file or directory

Additional info:
Many products, most notably Platform Symphony and VMWare check for the presence or absence of Xen by checking if this directory exists. The presence of this directory on non-Xen aware kernels breaks these checks and unexpected results occur.

Would be nice if a) it didn't do it at all or b) it was optional and invoked by the presence of a kernel parameter at boot to turn it on or turn it off - i.e. 

        kernel /vmlinuz-2.6.9-78.0.1.ELsmp ro root=/dev/vg00/root rhgb quiet noxen

Comment 2 Don Dutile (Red Hat) 2008-11-11 15:46:32 UTC
Doesn't have the same title, but it is a dupe of 460984,
and the patch has been submitted & built into the next
update (4.8).

See the above bz for a test kernel.

If needed/desired/required pre-4.8, request the z-stream
flags to be set in 460984 which will kick a process off to
have it put into a subsequent 4.7 z-stream update/release.

- Don

*** This bug has been marked as a duplicate of bug 460984 ***