Re: Kernel fails on Dreamcast - results of bisection

Adrian McMenamin
2009-03-22T18:30:46Z

On Mon, 2009-03-23 at 00:43 +0900, Paul Mundt wrote:
> On Sun, Mar 22, 2009 at 01:49:46PM +0000, Adrian McMenamin wrote:
> > On Sun, 2009-03-22 at 20:13 +0900, Paul Mundt wrote:
> > > On Sat, Mar 21, 2009 at 11:39:25PM +0000, Adrian McMenamin wrote:
> > > > (I am now getting a lot of messages about failures of the udev script -
> > > > possibly because I have just turned a lot of debugging stuff on - in any
> > > > case the system does boot and works with that commit reverted).
> > > >
> > > These messages are about allocation failures, the exact same thing that
> > > leads to your OOM. (It does help to actually read the error messages
> > > rather than dismiss them as superfluous). While it is possible that the
> > > timer patch pushed you over the edge on memory allocation, nothing else
> > > suggests that you have pinpointed the real problem. Obviously udev did
> > > not used to hit allocation failures, and we need to know when that
> > > started, or what you did to your environment that causes it.
> > > --
> >
> > Could you explain what you mean by "These messages are about allocation
> > failures, the exact same thing that leads to your OOM."
> >
> It seems pretty self evident. If a virtual filesystem is returning
> allocation failures, you have a problem, and you need to figure out why
> you are getting those allocation failures from udev. The timer patch
> might cause enough pressure that it makes the problem manifest in an oops
> more readily, but your system is completely broken or without the timer
> patch if you can't allocate pages to create device nodes, period.
>
> > Isn't one a failure to allocate space on a block device and the other
> > running out of memory, or have I missed something?
> >
> What do you think the backing store for udev is?

It's memory use is arbitrarily set in a config file. It's not the same
as running out of memory, just reaching that limit.

In any case I have not been able to reproduce those messages without the
debug options set to the max, but I have certainly been able to
reproduce the OOM condition.

There is clearly a regression here. I am puzzled about why you seem so
anxious not to acknowledge that there is.

Up to you.