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Broken /proc/stat

PostPosted: Mon May 30, 2011 3:56 pm
by linkfanel
Using linux 2.6.39 and grsecurity-2.2.2-2.6.39-201105251736.patch, CPU usage times reported in /proc/stat seem a bit off... A sample line:

cpu 22602 0 0 0 0 209909 0 0 0 0

top reports 100% in hi when the system should be idle. That's on i386; it seems to work fine on my 64 bit machine.

Re: Broken /proc/stat

PostPosted: Mon May 30, 2011 9:42 pm
by spender
I'm not able to reproduce this on either i386 or amd64. Have you tried a vanilla kernel?

-Brad

Re: Broken /proc/stat

PostPosted: Mon May 30, 2011 11:29 pm
by linkfanel
Yes, it works fine with a vanilla kernel. Here's my .config: http://www.linkfanel.net/stuff/config-2.6.39-grsec

Re: Broken /proc/stat

PostPosted: Tue May 31, 2011 7:51 am
by spender
Can you link to the vanilla config as well? Enabling grsecurity toggles some vanilla kernel config settings, so I'd want to make sure it wasn't due to one of those. I'll give it a look tonight. In the meantime, you could also try a binary search to find the problematic option if grsec is at fault.

-Brad

Re: Broken /proc/stat

PostPosted: Tue May 31, 2011 5:59 pm
by linkfanel
Vanilla config: http://www.linkfanel.net/stuff/config-2.6.39
The problem happens even with grsecurity disabled altogether.

Re: Broken /proc/stat

PostPosted: Tue May 31, 2011 8:55 pm
by spender
Can you test a kernel with just the latest PaX patch applied?

-Brad

Re: Broken /proc/stat

PostPosted: Tue May 31, 2011 9:46 pm
by linkfanel
I tested a kernel with just the PaX patch, and PaX disabled, but the problem is still there.

Re: Broken /proc/stat

PostPosted: Wed Jun 01, 2011 12:37 pm
by PaX Team
linkfanel wrote:I tested a kernel with just the PaX patch, and PaX disabled, but the problem is still there.
can you disable CGROUPS and tell me if you still see the problem? (mind you, stat/top are fine here even with the CGROUPS options enabled) also, does anyone else have this problem?

Re: Broken /proc/stat

PostPosted: Wed Jun 01, 2011 2:31 pm
by linkfanel
Yes, I disabled CGROUPS and the problem is still there.

Re: Broken /proc/stat

PostPosted: Wed Jul 06, 2011 1:41 pm
by PaX Team
the latest patches should fix the issue.

Re: Broken /proc/stat

PostPosted: Sun Jul 10, 2011 8:59 pm
by linkfanel
Yes, this issue is fixed. Thanks!