[PATCH] bluetooth : rfcomm tty BUG_ON() code fix
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STALE6845d
From: Dave Young <hidden>
Date: 2008-01-07 05:38:08
Also in:
lkml, netdev
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 <redacted> --- 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); }