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SubjectRe: [BUG] using smp_processor_id() in preemptible as suspending
Date
Am Mittwoch, 27. Februar 2008 schrieb Dave Young:
> On Wed, Feb 27, 2008 at 3:45 AM, Paul E. McKenney
> <paulmck@linux.vnet.ibm.com> wrote:
> > On Tue, Feb 26, 2008 at 08:33:54AM -0800, Andrew Morton wrote:
> > > On Tue, 26 Feb 2008 16:24:11 +0800 Dave Young <hidave.darkstar@gmail.com> wrote:
> > >
> > > > I don't know whom I should mail to, could you cc the proper guy? Thanks.
> >
> > Hello, Dave,
> >
> > Would you be willing to try out the following (untested, might not even
> > compile) patch show at the very end of this message? This assumes that
> > you were running with CONFIG_PREEMPT_RCU, which seems most likely based
> > on looking at your oops.
>
> Built ok, but can't even resume now. (dark screen with cursor blinking
> on top-left of minitor)

Dave, can you give this untested patch a try?

thanks,
Karsten

---
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index c7c5209..5a7f8fc 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -878,18 +878,20 @@ void rcu_offline_cpu(int cpu)
* Otherwise rcu_barrier() will fail
*/

- spin_lock_irqsave(&rdp->lock, flags);
+ local_irq_save(flags);
+
+ spin_lock(&rdp->lock);
rcu_offline_cpu_enqueue(rdp->donelist, rdp->donetail, list, tail);
for (i = GP_STAGES - 1; i >= 0; i--)
rcu_offline_cpu_enqueue(rdp->waitlist[i], rdp->waittail[i],
list, tail);
rcu_offline_cpu_enqueue(rdp->nextlist, rdp->nexttail, list, tail);
- spin_unlock_irqrestore(&rdp->lock, flags);
+ spin_unlock(&rdp->lock);
rdp->waitlistcount = 0;

/* Disengage the newly dead CPU from the grace-period computation. */

- spin_lock_irqsave(&rcu_ctrlblk.fliplock, flags);
+ spin_lock(&rcu_ctrlblk.fliplock);
rcu_check_mb(cpu);
if (per_cpu(rcu_flip_flag, cpu) == rcu_flipped) {
smp_mb(); /* Subsequent counter accesses must see new value */
@@ -906,7 +908,7 @@ void rcu_offline_cpu(int cpu)

cpu_clear(cpu, rcu_cpu_online_map);

- spin_unlock_irqrestore(&rcu_ctrlblk.fliplock, flags);
+ spin_unlock(&rcu_ctrlblk.fliplock);

/*
* Place the removed callbacks on the current CPU's queue.
@@ -919,11 +921,13 @@ void rcu_offline_cpu(int cpu)
*/

rdp = RCU_DATA_ME();
- spin_lock_irqsave(&rdp->lock, flags);
+ spin_lock(&rdp->lock);
*rdp->nexttail = list;
if (list)
rdp->nexttail = tail;
- spin_unlock_irqrestore(&rdp->lock, flags);
+ spin_unlock(&rdp->lock);
+
+ local_irq_restore(flags);
}

void __devinit rcu_online_cpu(int cpu)

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