[patch 20/27] hvc_console: Fix free_irq in spinlocked section

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: hvc_console-fix-free_irq-in-spinlocked-section.patch --]
[-- Type: text/plain, Size: 1935 bytes --]

2.6.27-stable review patch.  If anyone has any objections, please let us 
know.

------------------
From: Christian Borntraeger <borntraeger@de.ibm.com>

commit eef2622a9fcfa964073333ea72c7c9cd20ad45e6 upstream

hvc_console: Fix free_irq in spinlocked section

    commit 611e097d7707741a336a0677d9d69bec40f29f3d
    Author: Christian Borntraeger <borntraeger@de.ibm.com>
    hvc_console: rework setup to replace irq functions with callbacks
    introduced a spinlock recursion problem. The notifier_del is
    called with a lock held, and in turns calls free_irq which then
    complains when manipulating procfs. This fixes it by moving the
    call to the notifier to outside of the locked section.

Signed-off-by: Christian Borntraeger<borntraeger@de.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/char/hvc_console.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -367,13 +367,13 @@ static void hvc_close(struct tty_struct 
 	spin_lock_irqsave(&hp->lock, flags);
 
 	if (--hp->count == 0) {
-		if (hp->ops->notifier_del)
-			hp->ops->notifier_del(hp, hp->data);
-
 		/* We are done with the tty pointer now. */
 		hp->tty = NULL;
 		spin_unlock_irqrestore(&hp->lock, flags);
 
+		if (hp->ops->notifier_del)
+			hp->ops->notifier_del(hp, hp->data);
+
 		/*
 		 * Chain calls chars_in_buffer() and returns immediately if
 		 * there is no buffered data otherwise sleeps on a wait queue
@@ -416,11 +416,11 @@ static void hvc_hangup(struct tty_struct
 	hp->n_outbuf = 0;
 	hp->tty = NULL;
 
+	spin_unlock_irqrestore(&hp->lock, flags);
+
 	if (hp->ops->notifier_del)
 			hp->ops->notifier_del(hp, hp->data);
 
-	spin_unlock_irqrestore(&hp->lock, flags);
-
 	while(temp_open_count) {
 		--temp_open_count;
 		kref_put(&hp->kref, destroy_hvc_struct);

--