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authorChristian Borntraeger <borntraeger@de.ibm.com>2008-08-07 09:18:34 +0200
committerRusty Russell <rusty@rustcorp.com.au>2008-08-12 17:52:55 +1000
commitb1b135c8d619cb2c7045d6ee4e48375882518bb5 (patch)
tree7c48ccd12e2d01e548351f34bde77fb13f5dc513
parented6d68763b8b589c0ae9d231cbd72bd01f6685c5 (diff)
downloadlinux-b1b135c8d619cb2c7045d6ee4e48375882518bb5.tar.gz
fix spinlock recursion in hvc_console
commit 611e097d7707741a336a0677d9d69bec40f29f3d
Author: Christian Borntraeger <borntraeger@de.ibm.com>
hvc_console: rework setup to replace irq functions with callbacks
introduced a spinlock recursion problem.

request_irq tries to call the handler if the IRQ is shared.
The irq handler of hvc_console calls hvc_poll and hvc_kill
which might take the hvc_struct spinlock. Therefore, we have
to call request_irq outside the spinlock.

We can move the notifier_add safely outside the spinlock as ->data must
not be changed by the backend. Otherwise, tty_hangup would fail anyway.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--drivers/char/hvc_console.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 02aac104842d..fd64137b1ab9 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -322,11 +322,10 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
 
 	hp->tty = tty;
 
-	if (hp->ops->notifier_add)
-		rc = hp->ops->notifier_add(hp, hp->data);
-
 	spin_unlock_irqrestore(&hp->lock, flags);
 
+	if (hp->ops->notifier_add)
+		rc = hp->ops->notifier_add(hp, hp->data);
 
 	/*
 	 * If the notifier fails we return an error.  The tty layer