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| author | Inaky Perez-Gonzalez <inaky@linux.intel.com> | 2009-10-08 08:11:38 +0900 |
|---|---|---|
| committer | Inaky Perez-Gonzalez <inaky@linux.intel.com> | 2009-10-19 15:56:22 +0900 |
| commit | 4a78fd9a736db4c871bc8b583d66b61c38abd299 (patch) | |
| tree | 2f8e5c53eb81091c321436b70280b9627e673815 /drivers/net/wimax/i2400m/usb-tx.c | |
| parent | 0c96859d7a5f0286ed70d3c4e140ac6816a350da (diff) | |
| download | lwn-4a78fd9a736db4c871bc8b583d66b61c38abd299.tar.gz lwn-4a78fd9a736db4c871bc8b583d66b61c38abd299.zip | |
wimax/i2400m: fix oops caused by race condition when exiting USB kthreads
Current i2400m USB code had to threads (one for processing RX, one for
TX). When calling i2400m_{tx,rx}_release(), it would crash if the
thread had exited already due to an error.
So changed the code to have the thread fill in/out
i2400mu->{tx,rx}_kthread under a spinlock; then the _release()
function will call kthread_stop() only if {rx,tx}_kthread is still
set.
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Diffstat (limited to 'drivers/net/wimax/i2400m/usb-tx.c')
| -rw-r--r-- | drivers/net/wimax/i2400m/usb-tx.c | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/drivers/net/wimax/i2400m/usb-tx.c b/drivers/net/wimax/i2400m/usb-tx.c index 90dfff1afb8a..a3c46e99c804 100644 --- a/drivers/net/wimax/i2400m/usb-tx.c +++ b/drivers/net/wimax/i2400m/usb-tx.c @@ -161,9 +161,15 @@ int i2400mu_txd(void *_i2400mu) struct device *dev = &i2400mu->usb_iface->dev; struct i2400m_msg_hdr *tx_msg; size_t tx_msg_size; + unsigned long flags; d_fnstart(4, dev, "(i2400mu %p)\n", i2400mu); + spin_lock_irqsave(&i2400m->tx_lock, flags); + BUG_ON(i2400mu->tx_kthread != NULL); + i2400mu->tx_kthread = current; + spin_unlock_irqrestore(&i2400m->tx_lock, flags); + while (1) { d_printf(2, dev, "TX: waiting for messages\n"); tx_msg = NULL; @@ -183,6 +189,11 @@ int i2400mu_txd(void *_i2400mu) if (result < 0) break; } + + spin_lock_irqsave(&i2400m->tx_lock, flags); + i2400mu->tx_kthread = NULL; + spin_unlock_irqrestore(&i2400m->tx_lock, flags); + d_fnend(4, dev, "(i2400mu %p) = %d\n", i2400mu, result); return result; } @@ -213,11 +224,13 @@ int i2400mu_tx_setup(struct i2400mu *i2400mu) struct i2400m *i2400m = &i2400mu->i2400m; struct device *dev = &i2400mu->usb_iface->dev; struct wimax_dev *wimax_dev = &i2400m->wimax_dev; + struct task_struct *kthread; - i2400mu->tx_kthread = kthread_run(i2400mu_txd, i2400mu, "%s-tx", - wimax_dev->name); - if (IS_ERR(i2400mu->tx_kthread)) { - result = PTR_ERR(i2400mu->tx_kthread); + kthread = kthread_run(i2400mu_txd, i2400mu, "%s-tx", + wimax_dev->name); + /* the kthread function sets i2400mu->tx_thread */ + if (IS_ERR(kthread)) { + result = PTR_ERR(kthread); dev_err(dev, "TX: cannot start thread: %d\n", result); } return result; @@ -225,5 +238,17 @@ int i2400mu_tx_setup(struct i2400mu *i2400mu) void i2400mu_tx_release(struct i2400mu *i2400mu) { - kthread_stop(i2400mu->tx_kthread); + unsigned long flags; + struct i2400m *i2400m = &i2400mu->i2400m; + struct device *dev = i2400m_dev(i2400m); + struct task_struct *kthread; + + spin_lock_irqsave(&i2400m->tx_lock, flags); + kthread = i2400mu->tx_kthread; + i2400mu->tx_kthread = NULL; + spin_unlock_irqrestore(&i2400m->tx_lock, flags); + if (kthread) + kthread_stop(kthread); + else + d_printf(1, dev, "TX: kthread had already exited\n"); } |