On 01/23/2010 02:46 AM, kecsa@xxxxxxxxxxxxxxxx wrote:
Hi,
when I load b43 with hwtkip=1 system hangs after
' b43-phy0 debug: Using hardware based encryption for keyidx: 0, mac:...'
throwing the below BUG.
This is a non-SMP non-preemtive kernel. It looks like we are entering
b43_op_update_tkip_key() already holding the wl->mutex. We lock mutex in
b43_interrupt_thread_handler().
This problem is present in stable and also in compat-wireless-2010-01-22
shapshot if I haven't missed something. As a quick and dirty fix I have
removed wl->mutex lock/unlock from b43_op_update_tkip_key(). Box survived
one day (until now) and a ~3GB file transfer over WLAN using hwtkip in
this way.
Your analysis seem to be correct. I tested with the following patch, which tests
to see if the mutex is locked on entry. If not, it logs a message, locks the
mutex and sets a flag to indicate that the mutex should be unlocked on exit.
This patch is not SMP-safe, but is merely for testing. The printk statement has
not triggered after about 1 hour of testing. I'll give it a bit more testing
before a final patch is submitted.
Index: wireless-testing/drivers/net/wireless/b43/main.c
===================================================================
--- wireless-testing.orig/drivers/net/wireless/b43/main.c
+++ wireless-testing/drivers/net/wireless/b43/main.c
@@ -850,11 +850,16 @@ static void b43_op_update_tkip_key(struc
struct b43_wl *wl = hw_to_b43_wl(hw);
struct b43_wldev *dev;
int index = keyconf->hw_key_idx;
+ bool locked_here = 0;
if (B43_WARN_ON(!modparam_hwtkip))
return;
- mutex_lock(&wl->mutex);
+ if (!mutex_is_locked(&wl->mutex)) {
+ printk(KERN_DEBUG "b43: mutex not locked in %s\n", __func__);
+ mutex_lock(&wl->mutex);
+ locked_here = 1;
+ }
dev = wl->current_dev;
if (!dev || b43_status(dev) < B43_STAT_INITIALIZED)
@@ -866,7 +871,8 @@ static void b43_op_update_tkip_key(struc
keymac_write(dev, index, addr);
out_unlock:
- mutex_unlock(&wl->mutex);
+ if (locked_here)
+ mutex_unlock(&wl->mutex);
}
static void do_key_write(struct b43_wldev *dev,
==================================================
Larry
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