NX cannot be enabled: non-PAE kernel

[Michael Zintakis]

I have compiled a PAE kernel and installed it on my system (it *is* a 
PAE kernel, I am sure of it :-) ), but when I boot up I see the 
following message: "Notice: NX (Execute Disable) protection cannot be 
enabled: non-PAE kernel!"

I am certain I am using the right kernel and cannot explain why this 
error occurs. Could it be that the BIOS may have the NX-bit disabled (if 
so, how do I find out?) or is it something I am definitely doing wrong?

[Michael Zintakis]

Michael Zintakis wrote:
>  I have compiled a PAE kernel and installed it on my system (it *is* a
>
>  PAE kernel, I am sure of it :-) ), but when I boot up I see the 
>  following message: "Notice: NX (Execute Disable) protection cannot be 
>  enabled: non-PAE kernel!"
>
>  I am certain I am using the right kernel and cannot explain why this 
>  error occurs. Could it be that the BIOS may have the NX-bit disabled 
>  (if so, how do I find out?) or is it something I am definitely doing 
>  wrong? 
I found what is causing this.

I looked at config-i686-PAE and there was a comment related to 
CONFIG_I2O (I2O is not functioning in x86-32 PAE kernels) and I checked 
my .config file and there it was - activated, as I have a few I2O 
modules I use on my system. So, even though I selected the PAE-specific 
options (like MEM64G etc) and the end package produced was "kernel-PAE" 
the actual kernel was *not* PAE as CONFIG_I2O was silently deactivating 
all my PAE-related options.

Maybe this is a bug and I should at least had a warning and not banging 
my head against the wall for 2 days only to discover - by sheer chance - 
that I2O is incompatible with PAE and it is the reason I cannot produce 
PAE kernel even though my package was called "kernel-PAE"!


MZ