I'm having issues when using cow files with CentOS6 system images. It is specific to CentOS6. When I tried with a debian image built with debootstrap, the system booted just fine. I am experiencing this issue both with a custom built UML kernel as well as the kernel I obtained from the debian repository (2.6.32-1um-4+34squeeze1)
The issue I am experiencing is that during the boot process, udev hangs forever and the boot process does not complete. It only occurs when I use a cow file by specifying just the cow file on the command line like "ubd0=cow_fs" rather than "ubd0=cow_fs,root_fs". When I specify both the cow file and the backing file, the problem doesn't happen. I am able to specify ubd0 either way with a debian image and the system boots as expected. I have tried editing the appropriate rc script in the CentOS6 image to take udev out of the boot process, and the system boots, but has problems related to udev not running. I have also tried specifying the "udevtimeout" parameter on the kernel command line to see if I could force it to time out quickly and carry on with booting, but that made no difference. This leads me to believe that udev isn't just spinning it's wheels waiting for something, but it's actually hung or crashed. I'm kind of at a loss here. I don't know what interaction between the cow fs and udev would cause udev to hang, or if it's something that's only tangentially related to using the cow fs that's causing the problem. It may even be a bug in udev. I'm assuming that the kernel presents the block device ubd0/a to the system the same way, regardless if the device is specified to the kernel as "cow_file,backing_file" or just "cow_file", so I don't know why that would cause an issue. However, the manner that I use to specify ubd0 on the command line is literally the only thing that is different between a system that boots successfully, and one that hangs at starting udev. The environment in which I run the UML kernel doesn't seem to make a difference; I have run the kernel on both my Debian Squeeze box and one of our CentOS6 servers (which is where these machines will be running in production). Dan ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
