unable to handle kernel null pointer

[japrogramer]

http://i.imgur.com/NEozxDK.jpg

i suspect this has something with usb ;
i have a usb hub but the error occurs with both it connected and disconnected the error occours earlie

[japrogramer]

sometimes a similar error happens during boot right after " geting random seed" giving an error of null
the only thing i can think of that i have done with random is tried out the entropy bsed random i think it was in bcm2708_wog also i em using arch and have recently updated the firmware there after such errors show up now, rendering the pi unusable, i have also tried to fsck thee sdcard but it passed. i might have to flash another image into it ...

[popcornmix]

What does "uname -a" report?
Have you tried rpi-update?

[japrogramer]

alarmpi::% uname -a
Linux alarmpi 3.6.11-14-ARCH+ #1 PREEMPT Sun Jul 21 17:39:58 CDT 2013 armv6l GNU/Linux
alarmpi::%

im running arch on\t have rpi-update, also the problem happens when i connect an hdmi to vga converter i recently discovered... although i have been using the hdmi converter for aa while only recently did this begging to happen, so i can no longer connect the pi to a monitor if i want it to boot. powering the pi thru a powered usbhub is not working when i have the hdmi port in use as soon as i disconnect the hdmi it powered up ... i think it is drawing power

[japrogramer]

i have further reason to believe that it is something to do with usb
this error log snippet
http://pastebin.com/seJfYp5U

[popcornmix]

also the problem happens when i connect an hdmi to vga converter i recently discovered

Sounds like a power supply issue. VGA converter is taking too much current and dropping the voltage.
Can you measure the voltage here:
http://elinux.org/R-Pi_Troubleshooting#Troubleshooting_power_problems

[japrogramer]

Will try this as soon as my multi meter comes in from amazon, I tried a different power supply and so far have not seen any errors with it ... why all of a sudden my other power supply would create a kernel oops boggles my mind

[japrogramer]

Ok, the poly fuse is fine but when I go test the voltage on tp1 and tp2 it is 4.6 outside the recommended range of 4.75 and 5.25 volts even though I em using a 2 amp 5v power supply I still em going to test all my other power supplies but I would like to know how to test the power coming out of my USB hub and also the power coming directly from the charger the test leads are to big to fit in there

[japrogramer]

The problem does not occur as often with my 2 amp power supply compared to the 700 milli amp or 1 amp power supply
I have a wifi dongle keyboard and hdmi to vga converter connected, I have a powered usb hub but em not sure if it is safe to use since it used to be able to power the pi but now it can't atleast with the hdmi converter connected I know that I can use a sacrificial wire between the hub and the pi to clip the power cables therefore avoiding power issues but shouldn't it be able to power the pi it is a 1 amp powered hub

[ghollingworth]

It can be the fuse that is the problem if you've plugged in anything a little too hungry!

Try shorting out the fuse with a croc clip or some wire and see if that I'd the problem, or just measure the voltage across it

Gordon

[P33M]

I know of one possible cause of a crash in that function: it's if the root port detects a disconnect event and bad things happen. Disconnect events can potentially be caused by poor power causing downstream devices to shut down.

It should be one of the bugs that raspberrypi/linux#352 fixes.

Are you using a model A?

As Gordon says, you can half-cook the polyfuse if you draw slightly too much current but not enough to trip the fuse properly. If you measure TP1-TP2 and then measure across F3, add them together and this is the voltage coming out of the adapter. If your F3 is dropping more than about 100mV then you need to unplug the pi for several hours to let it reset.

The same may be true of your hub - some have polyfuses in and your HDMI adapter + pi may have semi-tripped that one too.

[japrogramer]

The poly fuse draws .003 v , when I try to power the pi with my usb hub tp1 and tp2 say it is only getting about 2.5 V not even enough to power it up which is weird because i used to power the pi from the very same hub before. when i power the pi from my 700ma power supply the error occurs the most often out of all often which delivers 4.8V into the pi but when the error occurs the measurement is 4.94V right before it even boots, with my 1 Amp power supply it gets thru booing with 4.8V but during use with xbmc it frezes randomly not even the lights on the pi or the wifi ddongle blink the voltage is 4.94V when it happens oddly enough with my 2 Amp power supply during boot the voltage is 4.72V when using xbmc it drops to 4.65V but this seems to be the most stable power supply in terms of the error showing up

[japrogramer]

I em using innova equus 3320 multimeter

[japrogramer]

also my uname -a recently change
Last login: Tue Aug 6 14:36:08 2013
alarmpi:~:% uname -a
Linux alarmpi 3.10.4-2-ARCH+ #1 PREEMPT Sun Aug 4 04:31:59 CDT 2013 armv6l GNU/Linux

[japrogramer]

Model b pi

[ghollingworth]

If the voltage between TP1 and TP2 is too low (below 4.75V) and the drop across the fuse is only 0.003v then this must mean the power supply is no good. what is the voltage on the USB power input.

There are many cheap power supplys that drop below 4.75 far before they reach their specified rating...

Gordon

[japrogramer]

The power supply is brand new, just came from amazon http://www.amazon.com/gp/aw/d/B009RXU59C/ref=ya_aw_oh_pii
But what is weird is that even though it is below the voltage range according to tp1 tp2 it produces the most stable pi ... I might have to recheck the polyfuse for this one but I em sure about the test point readings

[popcornmix]

Is this still an issue?

[japrogramer]

hasn't happened since my new powersupply arrived... but if it does I'll post