Unable to handle kernel paging request at virtual address ... while writing to frame buffer..

[Chan Kim]

Hi, Arun and Pramod,
Yes I knew this is from the page fault handling routine. (In my case, unhandled_fault function insdie do_sparc_fault function)
I know before the page fault, the pmd value (the value pointed to by pgd of context 1) was zero, so page fault occured.
This is the message I side-printed on the UART terminal. (If the frame buffer access was successful, the printk would have been on LCD but it didn't print on the LCD because of this paging error.)
The page fault handler should make a new pte for the frame buffer address but giving me this error.

Unable to handel kernel paging request at virtual address 696e1000
{mm,active_mm}->context = 00000001
{mm,active_mm}->pgd = c800a400
In what case can this happen? Any clue will be very helpful.
Thanks!
Chan

________________________________
From : "Arun KS" <getarunks at gmail.com>
Sent : 2014-03-27 18:27:57 ( +09:00 )
To : Chan Kim <ckim at etri.re.kr>
Cc : kernelnewbies at kernelnewbies.org <kernelnewbies at kernelnewbies.org>
Subject : Re: Unable to handle kernel paging request at virtual address ... while writing to frame buffer..

Hi Chan,

On Thu, Mar 27, 2014 at 2:25 PM, Chan Kim wrote:
> Hi,
> I have this 'unable to handle kernel paging request at virtual address ...'
This means the virtual address used doesn't have a proper mapping in
the page table.

Thanks,
Arun
> when writing to the frame buffer.
> Has anybody seen similar situation? and hopeful can tell me what the problem
> was?
> Thanks!
> Chan
>
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