An IRQ handler fix for arch/mips/dec/irq.c

["Maciej W. Rozycki" <macro@ds2.pg.gda.pl>]

Hi,

 The epilogue for the DECstation's IRQ handler is buggy -- it permits
infinite interrupt recursion which may lead to a stack overflow.  I wasn't
able to check if that's the reason of random crashes I get when I run
strace at the console, yet, but it might be -- the load might be up to 10k
interrupts per second if data is available in time.

 Please apply.

  Maciej

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +

patch-mips-2.4.0-do_irq-0
diff -up --recursive --new-file 
linux-mips-2.4.0-20010126.macro/arch/mips/dec/irq.c 
linux-mips-2.4.0-20010126/arch/mips/dec/irq.c
--- linux-mips-2.4.0-20010126.macro/arch/mips/dec/irq.c Sun Dec  3 05:26:46 2000
+++ linux-mips-2.4.0-20010126/arch/mips/dec/irq.c       Thu Feb  8 07:44:10 2001
@@ -136,8 +136,8 @@ asmlinkage void do_IRQ(int irq, struct p
        } while (action);
        if (do_random & SA_SAMPLE_RANDOM)
            add_interrupt_randomness(irq);
-       unmask_irq(irq);
        __cli();
+       unmask_irq(irq);
     }
     irq_exit(cpu, irq);