Re: [PATCH] update fix X86_64 procfs provide stack information forthreads

From: Stefani Seibold
Date: Wed Nov 04 2009 - 10:42:26 EST

Am Mittwoch, den 04.11.2009, 13:00 +0100 schrieb Andi Kleen:
> > This is true, but i think it is better to get an outdated value than a
> > complete wrong value like -1.
> -1 means "I don't know". I don't think "completely wrong"
> is the correct term to describe that.
> > The truth is that KSTK_ESP always return an outdated value on a multi
> > core system if the process never do a system call.
> I think not supporting updates on interrupts at least is very poor.
> Unfortunately there's no good way fast path way to detect this I know of
> (that is why I originally added -1 here)

This is a first draft for supporting interrupts:

unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
struct pt_regs *old_regs = set_irq_regs(regs);

/* high bit used in ret_from_ code */
unsigned vector = ~regs->orig_ax;
unsigned irq;


/* >>>>>>>> update usersp */
current->thread.usersp = regs->sp;

irq = __get_cpu_var(vector_irq)[vector];

if (!handle_irq(irq, regs)) {

if (printk_ratelimit())
pr_emerg("%s: %d.%d No irq handler for vector (irq %d)\n",
__func__, smp_processor_id(), vector, irq);


return 1;

This works in my environment, but i have not the oversight if it work
under all circumstances. And we need a similar line in the timer


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