Re: Linus rollup

[Andrea Arcangeli <andrea@suse.de>]

On Wed, Jan 29, 2003 at 02:35:52PM -0800, Stephen Hemminger wrote:
> On Wed, 2003-01-29 at 02:26, Andrew Morton wrote:
> > "David S. Miller" <davem@redhat.com> wrote:
> > >
> > >    From: Russell King <rmk@arm.linux.org.uk>
> > >    Date: Wed, 29 Jan 2003 09:59:49 +0000
> > >    
> > >    	/* This function must be called with interrupts disabled
> > >    
> > >    which hasn't been true for some time, and is even less true now that
> > >    local IRQs don't get disabled.  Does this matter... for UP?
> > > 
> > > I disable local IRQs during gettimeofday() on sparc.
> > > 
> > > These locks definitely need to be taken with IRQs disabled.
> > > Why isn't x86 doing that?
> > 
> > Darned if I know.  Looks like Andrea's kernel will deadlock if
> > arch/i386/kernel/time.c:timer_interrupt() takes i8253_lock
> > while that cpu is holding the same lock in do_slow_gettimeoffset().
> 
> Rather than disabling interrupts in the i386 do_gettimeofday
> why not just change spin_lock(&i8253_lock) to spin_lock_irqsave
> in timer_pit.c

as you can see from my patch, I agree

Andrea
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