From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Larry Finger , "David S. Miller" Subject: [ 16/77] b43: Fix lockdep splat on module unload Date: Fri, 1 Mar 2013 11:44:01 -0800 Message-Id: <20130301194353.717100295@linuxfoundation.org> In-Reply-To: <20130301194351.913471337@linuxfoundation.org> References: <20130301194351.913471337@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Larry Finger commit 63a02ce1c5c59baa40b99756492e3ec8d6b51483 upstream. On unload, b43 produces a lockdep warning that can be summarized in the following way: ====================================================== [ INFO: possible circular locking dependency detected ] 3.8.0-wl+ #117 Not tainted ------------------------------------------------------- modprobe/5557 is trying to acquire lock: ((&wl->firmware_load)){+.+.+.}, at: [] flush_work+0x0/0x2a0 but task is already holding lock: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x12/0x20 which lock already depends on the new lock. [ INFO: possible circular locking dependency detected ] ====================================================== The full output is available at http://lkml.indiana.edu/hypermail/linux/kernel/1302.3/00060.html. To summarize, commit 6b6fa58 added a 'cancel_work_sync(&wl->firmware_load)' call in the wrong place. The fix is to move the cancel_work_sync() call to b43_bcma_remove() and b43_ssb_remove(). Thanks to Johannes Berg and Michael Buesch for help in diagnosing the log output. Signed-off-by: Larry Finger Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/b43/main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/wireless/b43/main.c +++ b/drivers/net/wireless/b43/main.c @@ -4214,7 +4214,6 @@ redo: mutex_unlock(&wl->mutex); cancel_delayed_work_sync(&dev->periodic_work); cancel_work_sync(&wl->tx_work); - cancel_work_sync(&wl->firmware_load); mutex_lock(&wl->mutex); dev = wl->current_dev; if (!dev || b43_status(dev) < B43_STAT_STARTED) { @@ -5434,6 +5433,7 @@ static void b43_bcma_remove(struct bcma_ /* We must cancel any work here before unregistering from ieee80211, * as the ieee80211 unreg will destroy the workqueue. */ cancel_work_sync(&wldev->restart_work); + cancel_work_sync(&wl->firmware_load); B43_WARN_ON(!wl); if (!wldev->fw.ucode.data) @@ -5510,6 +5510,7 @@ static void b43_ssb_remove(struct ssb_de /* We must cancel any work here before unregistering from ieee80211, * as the ieee80211 unreg will destroy the workqueue. */ cancel_work_sync(&wldev->restart_work); + cancel_work_sync(&wl->firmware_load); B43_WARN_ON(!wl); if (!wldev->fw.ucode.data)