* [PATCH] bluetooth : rfcomm tty BUG_ON() code fix
@ 2008-01-07 5:41 Dave Young
2008-01-11 6:23 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Dave Young @ 2008-01-07 5:41 UTC (permalink / raw)
To: marcel; +Cc: davem, netdev, linux-kernel, bluez-devel
1) In tty.c the BUG_ON at line 115 will never be called, because the the before list_del_init in this same function.
115 BUG_ON(!list_empty(&dev->list));
So move the list_del_init to rfcomm_dev_del
2) The rfcomm_dev_del could be called from diffrent path (rfcomm_tty_hangup/rfcomm_dev_state_change/rfcomm_release_dev),
So add another BUG_ON when the rfcomm_dev_del is called more than one time.
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
---
net/bluetooth/rfcomm/tty.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff -upr linux/net/bluetooth/rfcomm/tty.c linux.new/net/bluetooth/rfcomm/tty.c
--- linux/net/bluetooth/rfcomm/tty.c 2008-01-07 13:20:17.000000000 +0800
+++ linux.new/net/bluetooth/rfcomm/tty.c 2008-01-07 13:25:17.000000000 +0800
@@ -95,9 +95,10 @@ static void rfcomm_dev_destruct(struct r
BT_DBG("dev %p dlc %p", dev, dlc);
- write_lock_bh(&rfcomm_dev_lock);
- list_del_init(&dev->list);
- write_unlock_bh(&rfcomm_dev_lock);
+ /* Refcount should only hit zero when called from rfcomm_dev_del()
+ which will have taken us off the list. Everything else are
+ refcounting bugs. */
+ BUG_ON(!list_empty(&dev->list));
rfcomm_dlc_lock(dlc);
/* Detach DLC if it's owned by this dev */
@@ -109,11 +110,6 @@ static void rfcomm_dev_destruct(struct r
tty_unregister_device(rfcomm_tty_driver, dev->id);
- /* Refcount should only hit zero when called from rfcomm_dev_del()
- which will have taken us off the list. Everything else are
- refcounting bugs. */
- BUG_ON(!list_empty(&dev->list));
-
kfree(dev);
/* It's safe to call module_put() here because socket still
@@ -313,7 +309,15 @@ static void rfcomm_dev_del(struct rfcomm
{
BT_DBG("dev %p", dev);
- set_bit(RFCOMM_TTY_RELEASED, &dev->flags);
+ if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags))
+ BUG_ON(1);
+ else
+ set_bit(RFCOMM_TTY_RELEASED, &dev->flags);
+
+ write_lock_bh(&rfcomm_dev_lock);
+ list_del_init(&dev->list);
+ write_unlock_bh(&rfcomm_dev_lock);
+
rfcomm_dev_put(dev);
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] bluetooth : rfcomm tty BUG_ON() code fix
2008-01-07 5:41 [PATCH] bluetooth : rfcomm tty BUG_ON() code fix Dave Young
@ 2008-01-11 6:23 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2008-01-11 6:23 UTC (permalink / raw)
To: hidave.darkstar; +Cc: marcel, netdev, linux-kernel, bluez-devel
From: Dave Young <hidave.darkstar@gmail.com>
Date: Mon, 7 Jan 2008 13:41:22 +0800
> 1) In tty.c the BUG_ON at line 115 will never be called, because the the before list_del_init in this same function.
> 115 BUG_ON(!list_empty(&dev->list));
> So move the list_del_init to rfcomm_dev_del
>
> 2) The rfcomm_dev_del could be called from diffrent path (rfcomm_tty_hangup/rfcomm_dev_state_change/rfcomm_release_dev),
> So add another BUG_ON when the rfcomm_dev_del is called more than one time.
>
> Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Applied, thanks Dave.
^ permalink raw reply [flat|nested] 2+ messages in thread
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