Bug 215378

Summary: udev eats 100% of cpu when adding 32+ ttys.
Product: Red Hat Enterprise Linux 4 Reporter: Scott Kilau <scottk>
Component: udevAssignee: Harald Hoyer <harald>
Status: CLOSED DUPLICATE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 4.0   
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OS: Linux   
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Last Closed: 2006-11-14 13:36:41 UTC Type: ---
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Description Scott Kilau 2006-11-13 18:53:47 UTC
Description of problem:
udev eats 100% of cpu for 5+ minutes when adding 32+ ttys using 
tty_register_device().

Version-Release number of selected component (if applicable):

Latest "up2date" for everything on ES 4.


How reproducible:

Every time.

Steps to Reproduce:
1. Add a driver to system that registers 32 ttys using the tty_register_device
() call in kernel.

2. With or without a "rule" for those devices in /etc/udev/rules.d, it doesn't 
matter.

  
Actual results:

System will literally be bogged down for 5-10 minutes, system hasn't panic'ed, 
but is horribly unresponsive for those 5-10 minutes.

An "uptime" will report load averages past 100!!!
A "ps -ef" (when it eventually responses) shows 100's and 100's of:

/bin/sh /sbin/hotplug tty
/etc/hotplug.d/default/20-hal.hotplug tty


Expected results:

Very minimal cpu usage.

The most important thing here is that under Fedora Core 4, 5 and 6,
this isn't a problem at all!

It works absolutely perfect uder FC 4, 5 and 6!




Additional info:

The udev version that appears to be in use on RH Enterprise 4 is "039".

This is *very* *very* old compared to FC 4, 5 or 6.
udev is currently up to "100" or so now!

I am guessing that something in "udev" has changed in newer versionf of udev 
that makes things work a lot crisper.

Why is udev not being kept up on RH 4?

Comment 1 Harald Hoyer 2006-11-14 13:36:41 UTC

*** This bug has been marked as a duplicate of 215379 ***