Re: [linux-usb-devel] khubd and ent:sda1 sucking CPU with reiser4+ USB HD

[Alan Stern]

On Wed, 7 Mar 2007, Eric Buddington wrote:

> On Wed, Mar 07, 2007 at 03:22:05PM -0500, Alan Stern wrote:
> > On Wed, 7 Mar 2007, Eric Buddington,,, wrote:
> > 
> > > > > So SysRq-t doesn't show anything about khubd, and SysRq-p doesn't give
> > > > > me anything at all. What else can I try?
> > 
> > How about SysRq-r?
> 
> SysRq : Keyboard mode set to XLATE

Whoops, I was thinking of SysRq-p, which you have already tried.

> > These problems start with some USB resets, right?  Did they occur with 
> > earlier kernel versions, or is this new behavior?
> 
> Yes, the problem starts with USB resets (or USB errors that trigger a reset)
> 
> > How often does the problem occur?
> 
> Recently, the USB drive has choked up after several hours of moderate
> use. However, before this instance, it would consistently hang up my
> watchdog process and force a system reboot (no idea why; the watchdog
> process didn't use this drive at all). This may have changed when I
> upgraded from 2.6.20-rc6-mm3 to 2.6.20-mm2, but my sample size is to
> small to be sure.

What about earlier kernels?  Does 2.6.19 work any better?

What about non -mm kernels, like 2.6.21-rc2?

I've never heard of a process failing to show up in a SysRq-t listing.  It 
suggests something is wrong with the process management in the kernel you 
were using.  That leads me to think a non -mm kernel might give more 
informative results.

And as long as you're testing, you might as well also turn on 
CONFIG_USB_DEBUG.

Alan Stern

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