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[PATCH] USB: ub 03 Oops with CFQ 

The blk_cleanup_queue does not necesserily destroy the queue. When we
destroy the corresponding ub_dev, it may leave the queue spinlock pointer
dangling.

This patch moves spinlocks from ub_dev to static memory. The locking
scheme is not changed. These spinlocks are still separate from the ub_lock.

Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Pete Zaitcev 2005-12-28 14:22:17 -08:00 committed by Greg Kroah-Hartman
parent b6daf7f508
commit 65b4fe553b
1 changed files with 45 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
drivers/block/ub.c
View File

@ -355,7 +355,7 @@ struct ub_lun {
* The USB device instance.
*/
struct ub_dev {
spinlock_t lock;
spinlock_t *lock;
atomic_t poison; /* The USB device is disconnected */
int openc; /* protected by ub_lock! */
/* kref is too implicit for our taste */
@ -452,6 +452,10 @@ MODULE_DEVICE_TABLE(usb, ub_usb_ids);
#define UB_MAX_HOSTS 26
static char ub_hostv[UB_MAX_HOSTS];
#define UB_QLOCK_NUM 5
static spinlock_t ub_qlockv[UB_QLOCK_NUM];
static int ub_qlock_next = 0;
static DEFINE_SPINLOCK(ub_lock); /* Locks globals and ->openc */
/*
@ -531,7 +535,7 @@ static ssize_t ub_diag_show(struct device *dev, struct device_attribute *attr,
return 0;
cnt = 0;
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
cnt += sprintf(page + cnt,
"poison %d reset %d\n",
@ -579,7 +583,7 @@ static ssize_t ub_diag_show(struct device *dev, struct device_attribute *attr,
if (++nc == SCMD_TRACE_SZ) nc = 0;
}
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
return cnt;
}
@ -626,6 +630,24 @@ static void ub_id_put(int id)
spin_unlock_irqrestore(&ub_lock, flags);
}
/*
* This is necessitated by the fact that blk_cleanup_queue does not
* necesserily destroy the queue. Instead, it may merely decrease q->refcnt.
* Since our blk_init_queue() passes a spinlock common with ub_dev,
* we have life time issues when ub_cleanup frees ub_dev.
*/
static spinlock_t *ub_next_lock(void)
{
unsigned long flags;
spinlock_t *ret;
spin_lock_irqsave(&ub_lock, flags);
ret = &ub_qlockv[ub_qlock_next];
ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM;
spin_unlock_irqrestore(&ub_lock, flags);
return ret;
}
/*
* Downcount for deallocation. This rides on two assumptions:
* - once something is poisoned, its refcount cannot grow
@ -1083,9 +1105,9 @@ static void ub_urb_timeout(unsigned long arg)
struct ub_dev *sc = (struct ub_dev *) arg;
unsigned long flags;
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
usb_unlink_urb(&sc->work_urb);
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
}
/*
@ -1108,10 +1130,10 @@ static void ub_scsi_action(unsigned long _dev)
struct ub_dev *sc = (struct ub_dev *) _dev;
unsigned long flags;
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
del_timer(&sc->work_timer);
ub_scsi_dispatch(sc);
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
}
static void ub_scsi_dispatch(struct ub_dev *sc)
@ -1754,7 +1776,7 @@ static void ub_reset_task(void *arg)
* queues of resets or anything. We do need a spinlock though,
* to interact with block layer.
*/
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
sc->reset = 0;
tasklet_schedule(&sc->tasklet);
list_for_each(p, &sc->luns) {
@ -1762,7 +1784,7 @@ static void ub_reset_task(void *arg)
blk_start_queue(lun->disk->queue);
}
wake_up(&sc->reset_wait);
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
}
/*
@ -1990,11 +2012,11 @@ static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun)
cmd->done = ub_probe_done;
cmd->back = &compl;
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
cmd->tag = sc->tagcnt++;
rc = ub_submit_scsi(sc, cmd);
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
if (rc != 0) {
printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */
@ -2052,11 +2074,11 @@ static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun,
cmd->done = ub_probe_done;
cmd->back = &compl;
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
cmd->tag = sc->tagcnt++;
rc = ub_submit_scsi(sc, cmd);
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
if (rc != 0) {
printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */
@ -2333,7 +2355,7 @@ static int ub_probe(struct usb_interface *intf,
if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
goto err_core;
memset(sc, 0, sizeof(struct ub_dev));
spin_lock_init(&sc->lock);
sc->lock = ub_next_lock();
INIT_LIST_HEAD(&sc->luns);
usb_init_urb(&sc->work_urb);
tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
@ -2483,7 +2505,7 @@ static int ub_probe_lun(struct ub_dev *sc, int lnum)
disk->driverfs_dev = &sc->intf->dev;
rc = -ENOMEM;
if ((q = blk_init_queue(ub_request_fn, &sc->lock)) == NULL)
if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL)
goto err_blkqinit;
disk->queue = q;
@ -2554,7 +2576,7 @@ static void ub_disconnect(struct usb_interface *intf)
* and the whole queue drains. So, we just use this code to
* print warnings.
*/
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
{
struct ub_scsi_cmd *cmd;
int cnt = 0;
@ -2571,7 +2593,7 @@ static void ub_disconnect(struct usb_interface *intf)
"%d was queued after shutdown\n", sc->name, cnt);
}
}
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
/*
* Unregister the upper layer.
@ -2590,19 +2612,15 @@ static void ub_disconnect(struct usb_interface *intf)
}
/*
* Taking a lock on a structure which is about to be freed
* is very nonsensual. Here it is largely a way to do a debug freeze,
* and a bracket which shows where the nonsensual code segment ends.
*
* Testing for -EINPROGRESS is always a bug, so we are bending
* the rules a little.
*/
spin_lock_irqsave(&sc->lock, flags);
spin_lock_irqsave(sc->lock, flags);
if (sc->work_urb.status == -EINPROGRESS) { /* janitors: ignore */
printk(KERN_WARNING "%s: "
"URB is active after disconnect\n", sc->name);
}
spin_unlock_irqrestore(&sc->lock, flags);
spin_unlock_irqrestore(sc->lock, flags);
/*
* There is virtually no chance that other CPU runs times so long
@ -2636,6 +2654,10 @@ static struct usb_driver ub_driver = {
static int __init ub_init(void)
{
int rc;
int i;
for (i = 0; i < UB_QLOCK_NUM; i++)
spin_lock_init(&ub_qlockv[i]);
if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
goto err_regblkdev;