Re: 2.6.3-rc2-mm1

[Zwane Mwaikambo]

On Thu, 12 Feb 2004, Andrew Morton wrote:

> Anton Blanchard <anton@xxxxxxxxx> wrote:
> >
> >
> > > This kernel and also 2.6.3-rc1-mm1 have a nasty bug which causes
> > > current->preempt_count to be decremented by one on each hard IRQ.  It
> > > manifests as a BUG() in the slab code early in boot.
> > >
> > > Disabling CONFIG_DEBUG_SPINLOCK_SLEEP will fix this up.  Do not use this
> > > feature on ia32, for it is bust.
> >
> > A few questions spring to mind. Like who wrote that dodgy patch?
>
> The dog wrote my homework?

I've not managed to trigger this one

CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_STACKOVERFLOW=y
# CONFIG_DEBUG_SLAB is not set
CONFIG_DEBUG_IOVIRT=y
CONFIG_DEBUG_SPINLOCK=y
CONFIG_DEBUG_PAGEALLOC=y
CONFIG_DEBUG_HIGHMEM=y
CONFIG_DEBUG_INFO=y
CONFIG_DEBUG_SPINLOCK_SLEEP=y

> > And any ideas how said person (who will remain nameless) broke ia32?
>
> Not really.  I spent a couple of hours debugging the darn thing, then gave
> up and used binary search to find the offending patch.
>
> <looks>
>
> include/asm-i386/hardirq.h:IRQ_EXIT_OFFSET needs treatment, I bet.
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