Re: [regression] boot failure on alpha, bisected

Thorsten Kranzkowski
2012-10-07T18:10:09Z

On Sun, Oct 07, 2012 at 07:13:00PM +0200, Oleg Nesterov wrote:
> On 10/07, Oleg Nesterov wrote:
> >
> > Hmm. I know nothing about arch/alpha and I can't understand its entry.S.
> > But _it seems_ to me that do_notify_resume() is called with irqs disabled.
> > If this is true, then imho arch/alpha should be fixed.
> >
> > Before this commit task_work_run() enabled irqs, but this was the "side
> > effect" of spin_lock_irq/spin_unlock_irq, we should not rely on this.
>
> Could you please test the debugging patch below?

Of course. With that patch applied the kernel (ac3d0da) boots again. The trace line
is printed about once a second, with values '2' and '4'.

Thorsten

>
> Oleg.
>
>
> --- x/arch/alpha/kernel/signal.c
> +++ x/arch/alpha/kernel/signal.c
> @@ -567,11 +567,19 @@ do_signal(struct pt_regs * regs, struct
> ptrace_set_bpt(current); /* re-set breakpoint */
> }
>
> +#include <linux/ratelimit.h>
> +
> void
> do_notify_resume(struct pt_regs *regs, struct switch_stack *sw,
> unsigned long thread_info_flags,
> unsigned long r0, unsigned long r19)
> {
> + if (irqs_disabled()) {
> + printk_ratelimited(KERN_WARNING
> + "NOTIFY with irqs_disabled:%lx\n", thread_info_flags);
> + local_irq_enable();
> + }
> +
> if (thread_info_flags & _TIF_SIGPENDING)
> do_signal(regs, sw, r0, r19);
>
>

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