Re: [Bug 7505] Linux-2.6.18 fails to boot on AMD64 machine

[Andrew Morton]

On Fri, 22 Dec 2006 09:22:48 +0100
Ard -kwaak- van Breemen <ard@xxxxxxxxxxxxxxx> wrote:

> Hello,
> On Fri, Dec 22, 2006 at 12:41:46PM +0800, Zhang, Yanmin wrote:
> > I think parse_args enables irq when it calls callbacks.
> > Could you try below?
> > 1) Test Andrew's patch of sema down_write;
> > 2) Apply below patch and see what the output is when booting. If the output has
> > "[BUG]..address.", Pls. map the address to function name by System.map.
> Without proof^H^H^H^H^Hpasting my dmesg and the "diff", I already
> concluded that ide_setup was the culprit. (I've debuged
> parse_one, and it barfed around the 3rd parameter which is
> hdb=noprobe).
> Anyway, a bad night of sleep reminds me that our EM64T boxes also
> have this line (which actually is a remainder of our VA1220 boxes
> ;-) ), and they don't barf, so it must be either the combination
> of the sata_nv together with the pata driver part, *or* just the
> pata driver part. (Our opteron != nforce chipsets also works).
> 

I expect that you'll find that the ide code ends up doing
down_write(pci_bus_sem), which will enable interrupts.

(We don't know which interrupt is pending this early - that'd be
interesting to find out, but we shouldn't be enabling interrupts in there).

To whom do I have to pay how much to get this darn patch tested?



--- a/lib/rwsem-spinlock.c~down_write-preserve-local-irqs
+++ a/lib/rwsem-spinlock.c
@@ -195,13 +195,14 @@ void fastcall __sched __down_write_neste
 {
 	struct rwsem_waiter waiter;
 	struct task_struct *tsk;
+	unsigned long flags;
 
-	spin_lock_irq(&sem->wait_lock);
+	spin_lock_irqsave(&sem->wait_lock, flags);
 
 	if (sem->activity == 0 && list_empty(&sem->wait_list)) {
 		/* granted */
 		sem->activity = -1;
-		spin_unlock_irq(&sem->wait_lock);
+		spin_unlock_irqrestore(&sem->wait_lock, flags);
 		goto out;
 	}
 
@@ -216,7 +217,7 @@ void fastcall __sched __down_write_neste
 	list_add_tail(&waiter.list, &sem->wait_list);
 
 	/* we don't need to touch the semaphore struct anymore */
-	spin_unlock_irq(&sem->wait_lock);
+	spin_unlock_irqrestore(&sem->wait_lock, flags);
 
 	/* wait to be given the lock */
 	for (;;) {
_

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