This is a note to let you know that I've just added the patch titled
b43: Fix lockdep splat on module unload
to the 3.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
b43-fix-lockdep-splat-on-module-unload.patch
and it can be found in the queue-3.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 63a02ce1c5c59baa40b99756492e3ec8d6b51483 Mon Sep 17 00:00:00 2001
From: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
Date: Mon, 25 Feb 2013 06:09:24 +0000
Subject: b43: Fix lockdep splat on module unload
From: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
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: [<ffffffff81062160>] flush_work+0x0/0x2a0
but task is already holding lock:
(rtnl_mutex){+.+.+.}, at: [<ffffffff813bd7d2>] 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 <Larry.Finger@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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)
Patches currently in stable-queue which might be from Larry.Finger@xxxxxxxxxxxx are
queue-3.8/b43-fix-lockdep-splat-on-module-unload.patch
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