The patch titled
     Fix crash with irqpoll due to the IRQF_IRQPOLL flag
has been added to the -mm tree.  Its filename is
     fix-crash-with-irqpoll-due-to-the-irqf_irqpoll-flag.patch

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: Fix crash with irqpoll due to the IRQF_IRQPOLL flag
From: Bernhard Walle <[EMAIL PROTECTED]>

o System crashes if booted with irqpoll command line option.

o Problem happens because Inside note_interrupt() we are accessing
  desc->action->flag without taking the desc->lock. While accessing it
  somebody goes ahead and unregisters the irq handler hence desc->action
  is NULL. By the time note_interrupt() checks it, it crashes.

o In that system it is irq 4 serving the serial driver.

o Take the desc->lock before accessing desc->action->flag.

Signed-off-by: Bernhard Walle <[EMAIL PROTECTED]>
Signed-off-by: Vivek Goyal <[EMAIL PROTECTED]>
Cc: Ingo Molnar <[EMAIL PROTECTED]>
Cc: Thomas Gleixner <[EMAIL PROTECTED]>
Cc: Alan Cox <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---

 kernel/irq/spurious.c |   23 ++++++++++++++++++++---
 1 files changed, 20 insertions(+), 3 deletions(-)

diff -puN 
kernel/irq/spurious.c~fix-crash-with-irqpoll-due-to-the-irqf_irqpoll-flag 
kernel/irq/spurious.c
--- a/kernel/irq/spurious.c~fix-crash-with-irqpoll-due-to-the-irqf_irqpoll-flag
+++ a/kernel/irq/spurious.c
@@ -138,6 +138,8 @@ report_bad_irq(unsigned int irq, struct 
 void note_interrupt(unsigned int irq, struct irq_desc *desc,
                    irqreturn_t action_ret)
 {
+       int call_misrouted_irq = 0;
+
        if (unlikely(action_ret != IRQ_HANDLED)) {
                desc->irqs_unhandled++;
                if (unlikely(action_ret != IRQ_NONE))
@@ -146,9 +148,24 @@ void note_interrupt(unsigned int irq, st
 
        if (unlikely(irqfixup)) {
                /* Don't punish working computers */
-               if ((irqfixup == 2 && ((irq == 0) ||
-                               (desc->action->flags & IRQF_IRQPOLL))) ||
-                               action_ret == IRQ_NONE) {
+               if (action_ret == IRQ_NONE)
+                       /* Nobody handled irq. Possibly a misrouted one. */
+                       call_misrouted_irq = 1;
+               else if (irqfixup == 2) {
+                       /* irqpoll is enabled. Is this the irq driving
+                        * polling.
+                        */
+                       if (irq == 0)
+                               call_misrouted_irq = 1;
+                       else {
+                               spin_lock(&desc->lock);
+                               if (desc->action &&
+                                       (desc->action->flags & IRQF_IRQPOLL))
+                                       call_misrouted_irq = 1;
+                               spin_unlock(&desc->lock);
+                       }
+               }
+               if (call_misrouted_irq) {
                        int ok = misrouted_irq(irq);
                        if (action_ret == IRQ_NONE)
                                desc->irqs_unhandled -= ok;
_

Patches currently in -mm which might be from [EMAIL PROTECTED] are

git-r8169.patch
scsi-remove-__gfp_dma.patch
fix-crash-with-irqpoll-due-to-the-irqf_irqpoll-flag.patch

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