[PATCH] alpha show_interrups() trashes argument
Eric Sesterhenn [Wed, 1 Feb 2006 11:06:13 +0000 (03:06 -0800)]
This is a bug found by cpminer.  The show_interrupts function reuses i as a
for loop counter, and therefore trashes its contents, which are needed
later.

(akpm: rename local `i' to `irq', use for_each_inline_cpu())

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/alpha/kernel/irq.c

index 76be5cf..9006063 100644 (file)
@@ -68,34 +68,32 @@ show_interrupts(struct seq_file *p, void *v)
 #ifdef CONFIG_SMP
        int j;
 #endif
-       int i = *(loff_t *) v;
+       int irq = *(loff_t *) v;
        struct irqaction * action;
        unsigned long flags;
 
 #ifdef CONFIG_SMP
-       if (i == 0) {
+       if (irq == 0) {
                seq_puts(p, "           ");
-               for (i = 0; i < NR_CPUS; i++)
-                       if (cpu_online(i))
-                               seq_printf(p, "CPU%d       ", i);
+               for_each_online_cpu(j)
+                       seq_printf(p, "CPU%d       ", j);
                seq_putc(p, '\n');
        }
 #endif
 
-       if (i < ACTUAL_NR_IRQS) {
-               spin_lock_irqsave(&irq_desc[i].lock, flags);
-               action = irq_desc[i].action;
+       if (irq < ACTUAL_NR_IRQS) {
+               spin_lock_irqsave(&irq_desc[irq].lock, flags);
+               action = irq_desc[irq].action;
                if (!action) 
                        goto unlock;
-               seq_printf(p, "%3d: ",i);
+               seq_printf(p, "%3d: ", irq);
 #ifndef CONFIG_SMP
-               seq_printf(p, "%10u ", kstat_irqs(i));
+               seq_printf(p, "%10u ", kstat_irqs(irq));
 #else
-               for (j = 0; j < NR_CPUS; j++)
-                       if (cpu_online(j))
-                               seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
+               for_each_online_cpu(j)
+                       seq_printf(p, "%10u ", kstat_cpu(j).irqs[irq]);
 #endif
-               seq_printf(p, " %14s", irq_desc[i].handler->typename);
+               seq_printf(p, " %14s", irq_desc[irq].handler->typename);
                seq_printf(p, "  %c%s",
                        (action->flags & SA_INTERRUPT)?'+':' ',
                        action->name);
@@ -108,13 +106,12 @@ show_interrupts(struct seq_file *p, void *v)
 
                seq_putc(p, '\n');
 unlock:
-               spin_unlock_irqrestore(&irq_desc[i].lock, flags);
-       } else if (i == ACTUAL_NR_IRQS) {
+               spin_unlock_irqrestore(&irq_desc[irq].lock, flags);
+       } else if (irq == ACTUAL_NR_IRQS) {
 #ifdef CONFIG_SMP
                seq_puts(p, "IPI: ");
-               for (i = 0; i < NR_CPUS; i++)
-                       if (cpu_online(i))
-                               seq_printf(p, "%10lu ", cpu_data[i].ipi_count);
+               for_each_online_cpu(j)
+                       seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
                seq_putc(p, '\n');
 #endif
                seq_printf(p, "ERR: %10lu\n", irq_err_count);
@@ -122,7 +119,6 @@ unlock:
        return 0;
 }
 
-
 /*
  * handle_irq handles all normal device IRQ's (the special
  * SMP cross-CPU interrupts have their own specific