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hso: Fix free of mutexes still in use.
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A new structure hso_mutex_table had to be declared statically
& used as as hso_device mutex_lock(&serial->parent->mutex) etc
is freed in hso_serial_open & hso_serial_close by kref_put while
the mutex is still in use.

This is a substantial change but should make the driver much stabler.

Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Denis Joseph Barrow authored and David S. Miller committed Nov 25, 2008
1 parent 89930b7 commit 52429eb
Showing 1 changed file with 87 additions and 23 deletions.
110 changes: 87 additions & 23 deletions drivers/net/usb/hso.c
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Original file line number Diff line number Diff line change
Expand Up @@ -230,6 +230,11 @@ struct hso_serial {
struct work_struct retry_unthrottle_workqueue;
};

struct hso_mutex_t {
struct mutex mutex;
u8 allocated;
};

struct hso_device {
union {
struct hso_serial *dev_serial;
Expand All @@ -248,7 +253,7 @@ struct hso_device {

struct device *dev;
struct kref ref;
struct mutex mutex;
struct hso_mutex_t *mutex;
};

/* Type of interface */
Expand Down Expand Up @@ -364,6 +369,13 @@ static struct hso_device *network_table[HSO_MAX_NET_DEVICES];
static spinlock_t serial_table_lock;
static struct ktermios *hso_serial_termios[HSO_SERIAL_TTY_MINORS];
static struct ktermios *hso_serial_termios_locked[HSO_SERIAL_TTY_MINORS];
/* hso_mutex_table has to be declared statically as hso_device
* is freed in hso_serial_open & hso_serial_close while
* the mutex is still in use.
*/
#define HSO_NUM_MUTEXES (HSO_SERIAL_TTY_MINORS+HSO_MAX_NET_DEVICES)
static struct hso_mutex_t hso_mutex_table[HSO_NUM_MUTEXES];
static spinlock_t hso_mutex_lock;

static const s32 default_port_spec[] = {
HSO_INTF_MUX | HSO_PORT_NETWORK,
Expand Down Expand Up @@ -604,6 +616,34 @@ static void set_serial_by_index(unsigned index, struct hso_serial *serial)
spin_unlock_irqrestore(&serial_table_lock, flags);
}


static struct hso_mutex_t *hso_get_free_mutex(void)
{
int index;
struct hso_mutex_t *curr_hso_mutex;

spin_lock(&hso_mutex_lock);
for (index = 0; index < HSO_NUM_MUTEXES; index++) {
curr_hso_mutex = &hso_mutex_table[index];
if (!curr_hso_mutex->allocated) {
curr_hso_mutex->allocated = 1;
spin_unlock(&hso_mutex_lock);
return curr_hso_mutex;
}
}
printk(KERN_ERR "BUG %s: no free hso_mutexs devices in table\n"
, __func__);
spin_unlock(&hso_mutex_lock);
return NULL;
}

static void hso_free_mutex(struct hso_mutex_t *mutex)
{
spin_lock(&hso_mutex_lock);
mutex->allocated = 0;
spin_unlock(&hso_mutex_lock);
}

/* log a meaningful explanation of an USB status */
static void log_usb_status(int status, const char *function)
{
Expand Down Expand Up @@ -1225,7 +1265,9 @@ void hso_unthrottle_workfunc(struct work_struct *work)
static int hso_serial_open(struct tty_struct *tty, struct file *filp)
{
struct hso_serial *serial = get_serial_by_index(tty->index);
int result;
int result1 = 0, result2 = 0;
struct mutex *hso_mutex = NULL;
int refcnt = 1;

/* sanity check */
if (serial == NULL || serial->magic != HSO_SERIAL_MAGIC) {
Expand All @@ -1234,14 +1276,15 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
return -ENODEV;
}

mutex_lock(&serial->parent->mutex);
hso_mutex = &serial->parent->mutex->mutex;
mutex_lock(hso_mutex);
/* check for port already opened, if not set the termios */
/* The serial->open count needs to be here as hso_serial_close
* will be called even if hso_serial_open returns -ENODEV.
*/
serial->open_count++;
result = usb_autopm_get_interface(serial->parent->interface);
if (result < 0)
result1 = usb_autopm_get_interface(serial->parent->interface);
if (result1 < 0)
goto err_out;

D1("Opening %d", serial->minor);
Expand All @@ -1261,11 +1304,10 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
(unsigned long)serial);
INIT_WORK(&serial->retry_unthrottle_workqueue,
hso_unthrottle_workfunc);
result = hso_start_serial_device(serial->parent, GFP_KERNEL);
if (result) {
result2 = hso_start_serial_device(serial->parent, GFP_KERNEL);
if (result2) {
hso_stop_serial_device(serial->parent);
serial->open_count--;
kref_put(&serial->parent->ref, hso_serial_ref_free);
}
} else {
D1("Port was already open");
Expand All @@ -1274,35 +1316,42 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
usb_autopm_put_interface(serial->parent->interface);

/* done */
if (result)
if (result1)
hso_serial_tiocmset(tty, NULL, TIOCM_RTS | TIOCM_DTR, 0);
err_out:
mutex_unlock(&serial->parent->mutex);
return result;
if (result2)
refcnt = kref_put(&serial->parent->ref, hso_serial_ref_free);
mutex_unlock(hso_mutex);
if (refcnt == 0)
hso_free_mutex(container_of(hso_mutex,
struct hso_mutex_t, mutex));
return result1 == 0 ? result2 : result1;
}

/* close the requested serial port */
static void hso_serial_close(struct tty_struct *tty, struct file *filp)
{
struct hso_serial *serial = tty->driver_data;
u8 usb_gone;
struct mutex *hso_mutex;
int refcnt;

D1("Closing serial port");
if (serial == NULL || serial->magic != HSO_SERIAL_MAGIC) {
D1("invalid serial structure bailing out.\n");
return;
}

mutex_lock(&serial->parent->mutex);
usb_gone = serial->parent->usb_gone;
hso_mutex = &serial->parent->mutex->mutex;
mutex_lock(hso_mutex);

if (!usb_gone)
usb_autopm_get_interface(serial->parent->interface);

/* reset the rts and dtr */
/* do the actual close */
serial->open_count--;
kref_put(&serial->parent->ref, hso_serial_ref_free);
if (serial->open_count <= 0) {
serial->open_count = 0;
if (serial->tty) {
Expand All @@ -1317,8 +1366,11 @@ static void hso_serial_close(struct tty_struct *tty, struct file *filp)

if (!usb_gone)
usb_autopm_put_interface(serial->parent->interface);

mutex_unlock(&serial->parent->mutex);
refcnt = kref_put(&serial->parent->ref, hso_serial_ref_free);
mutex_unlock(hso_mutex);
if (refcnt == 0)
hso_free_mutex(container_of(hso_mutex,
struct hso_mutex_t, mutex));
}

/* close the requested serial port */
Expand Down Expand Up @@ -2084,8 +2136,12 @@ static struct hso_device *hso_create_device(struct usb_interface *intf,
hso_dev->usb = interface_to_usbdev(intf);
hso_dev->interface = intf;
kref_init(&hso_dev->ref);
mutex_init(&hso_dev->mutex);

hso_dev->mutex = hso_get_free_mutex();
if (!hso_dev->mutex) {
kfree(hso_dev);
return NULL;
}
mutex_init(&hso_dev->mutex->mutex);
INIT_WORK(&hso_dev->async_get_intf, async_get_intf);
INIT_WORK(&hso_dev->async_put_intf, async_put_intf);

Expand Down Expand Up @@ -2131,7 +2187,7 @@ static void hso_free_net_device(struct hso_device *hso_dev)
unregister_netdev(hso_net->net);
free_netdev(hso_net->net);
}

hso_free_mutex(hso_dev->mutex);
hso_free_device(hso_dev);
}

Expand Down Expand Up @@ -2180,14 +2236,14 @@ static int hso_radio_toggle(void *data, enum rfkill_state state)
int enabled = (state == RFKILL_STATE_ON);
int rv;

mutex_lock(&hso_dev->mutex);
mutex_lock(&hso_dev->mutex->mutex);
if (hso_dev->usb_gone)
rv = 0;
else
rv = usb_control_msg(hso_dev->usb, usb_rcvctrlpipe(hso_dev->usb, 0),
enabled ? 0x82 : 0x81, 0x40, 0, 0, NULL, 0,
USB_CTRL_SET_TIMEOUT);
mutex_unlock(&hso_dev->mutex);
mutex_unlock(&hso_dev->mutex->mutex);
return rv;
}

Expand Down Expand Up @@ -2795,17 +2851,21 @@ static void hso_free_interface(struct usb_interface *interface)
{
struct hso_serial *hso_dev;
int i;
struct mutex *hso_mutex = NULL;
int refcnt = 1;

for (i = 0; i < HSO_SERIAL_TTY_MINORS; i++) {
if (serial_table[i]
&& (serial_table[i]->interface == interface)) {
hso_dev = dev2ser(serial_table[i]);
if (hso_dev->tty)
tty_hangup(hso_dev->tty);
mutex_lock(&hso_dev->parent->mutex);
hso_mutex = &hso_dev->parent->mutex->mutex;
mutex_lock(hso_mutex);
hso_dev->parent->usb_gone = 1;
mutex_unlock(&hso_dev->parent->mutex);
kref_put(&serial_table[i]->ref, hso_serial_ref_free);
refcnt = kref_put(&serial_table[i]->ref,
hso_serial_ref_free);
mutex_unlock(hso_mutex);
}
}

Expand All @@ -2824,6 +2884,9 @@ static void hso_free_interface(struct usb_interface *interface)
hso_free_net_device(network_table[i]);
}
}
if (refcnt == 0)
hso_free_mutex(container_of(hso_mutex,
struct hso_mutex_t, mutex));
}

/* Helper functions */
Expand Down Expand Up @@ -2922,6 +2985,7 @@ static int __init hso_init(void)

/* Initialise the serial table semaphore and table */
spin_lock_init(&serial_table_lock);
spin_lock_init(&hso_mutex_lock);
for (i = 0; i < HSO_SERIAL_TTY_MINORS; i++)
serial_table[i] = NULL;

Expand Down

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