From 860e41a71c1731e79e1920dc42676bafc925af5e Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Sat, 27 Feb 2010 20:54:24 +0100 Subject: [PATCH] usb: cdc-wdm: Fix race between write and disconnect Unify mutexes to fix a race between write and disconnect and shift the test for disconnection to always report it. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-wdm.c | 84 ++++++++++++++++++++----------------- 1 file changed, 45 insertions(+), 39 deletions(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 18aafcb08fc8..cf1c5fb918dc 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -87,9 +87,7 @@ struct wdm_device { int count; dma_addr_t shandle; dma_addr_t ihandle; - struct mutex wlock; - struct mutex rlock; - struct mutex plock; + struct mutex lock; wait_queue_head_t wait; struct work_struct rxwork; int werr; @@ -305,14 +303,38 @@ static ssize_t wdm_write if (we < 0) return -EIO; - r = mutex_lock_interruptible(&desc->wlock); /* concurrent writes */ + desc->outbuf = buf = kmalloc(count, GFP_KERNEL); + if (!buf) { + rv = -ENOMEM; + goto outnl; + } + + r = copy_from_user(buf, buffer, count); + if (r > 0) { + kfree(buf); + rv = -EFAULT; + goto outnl; + } + + /* concurrent writes and disconnect */ + r = mutex_lock_interruptible(&desc->lock); rv = -ERESTARTSYS; - if (r) + if (r) { + kfree(buf); goto outnl; + } + + if (test_bit(WDM_DISCONNECTING, &desc->flags)) { + kfree(buf); + rv = -ENODEV; + goto outnp; + } r = usb_autopm_get_interface(desc->intf); - if (r < 0) + if (r < 0) { + kfree(buf); goto outnp; + } if (!file->f_flags && O_NONBLOCK) r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE, @@ -320,24 +342,8 @@ static ssize_t wdm_write else if (test_bit(WDM_IN_USE, &desc->flags)) r = -EAGAIN; - if (r < 0) - goto out; - - if (test_bit(WDM_DISCONNECTING, &desc->flags)) { - rv = -ENODEV; - goto out; - } - - desc->outbuf = buf = kmalloc(count, GFP_KERNEL); - if (!buf) { - rv = -ENOMEM; - goto out; - } - - r = copy_from_user(buf, buffer, count); - if (r > 0) { + if (r < 0) { kfree(buf); - rv = -EFAULT; goto out; } @@ -374,7 +380,7 @@ static ssize_t wdm_write out: usb_autopm_put_interface(desc->intf); outnp: - mutex_unlock(&desc->wlock); + mutex_unlock(&desc->lock); outnl: return rv < 0 ? rv : count; } @@ -387,7 +393,7 @@ static ssize_t wdm_read struct wdm_device *desc = file->private_data; - rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */ + rv = mutex_lock_interruptible(&desc->lock); /*concurrent reads */ if (rv < 0) return -ERESTARTSYS; @@ -465,7 +471,7 @@ retry: rv = cntr; err: - mutex_unlock(&desc->rlock); + mutex_unlock(&desc->lock); if (rv < 0 && rv != -EAGAIN) dev_err(&desc->intf->dev, "wdm_read: exit error\n"); return rv; @@ -533,7 +539,7 @@ static int wdm_open(struct inode *inode, struct file *file) } intf->needs_remote_wakeup = 1; - mutex_lock(&desc->plock); + mutex_lock(&desc->lock); if (!desc->count++) { rv = usb_submit_urb(desc->validity, GFP_KERNEL); if (rv < 0) { @@ -544,7 +550,7 @@ static int wdm_open(struct inode *inode, struct file *file) } else { rv = 0; } - mutex_unlock(&desc->plock); + mutex_unlock(&desc->lock); usb_autopm_put_interface(desc->intf); out: mutex_unlock(&wdm_mutex); @@ -556,9 +562,9 @@ static int wdm_release(struct inode *inode, struct file *file) struct wdm_device *desc = file->private_data; mutex_lock(&wdm_mutex); - mutex_lock(&desc->plock); + mutex_lock(&desc->lock); desc->count--; - mutex_unlock(&desc->plock); + mutex_unlock(&desc->lock); if (!desc->count) { dev_dbg(&desc->intf->dev, "wdm_release: cleanup"); @@ -655,9 +661,7 @@ next_desc: desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL); if (!desc) goto out; - mutex_init(&desc->wlock); - mutex_init(&desc->rlock); - mutex_init(&desc->plock); + mutex_init(&desc->lock); spin_lock_init(&desc->iuspin); init_waitqueue_head(&desc->wait); desc->wMaxCommand = maxcom; @@ -772,7 +776,9 @@ static void wdm_disconnect(struct usb_interface *intf) clear_bit(WDM_IN_USE, &desc->flags); spin_unlock_irqrestore(&desc->iuspin, flags); cancel_work_sync(&desc->rxwork); + mutex_lock(&desc->lock); kill_urbs(desc); + mutex_unlock(&desc->lock); wake_up_all(&desc->wait); if (!desc->count) cleanup(desc); @@ -786,7 +792,7 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message) dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor); - mutex_lock(&desc->plock); + mutex_lock(&desc->lock); #ifdef CONFIG_PM if ((message.event & PM_EVENT_AUTO) && test_bit(WDM_IN_USE, &desc->flags)) { @@ -798,7 +804,7 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message) #ifdef CONFIG_PM } #endif - mutex_unlock(&desc->plock); + mutex_unlock(&desc->lock); return rv; } @@ -821,9 +827,9 @@ static int wdm_resume(struct usb_interface *intf) int rv; dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor); - mutex_lock(&desc->plock); + mutex_lock(&desc->lock); rv = recover_from_urb_loss(desc); - mutex_unlock(&desc->plock); + mutex_unlock(&desc->lock); return rv; } @@ -831,7 +837,7 @@ static int wdm_pre_reset(struct usb_interface *intf) { struct wdm_device *desc = usb_get_intfdata(intf); - mutex_lock(&desc->plock); + mutex_lock(&desc->lock); return 0; } @@ -841,7 +847,7 @@ static int wdm_post_reset(struct usb_interface *intf) int rv; rv = recover_from_urb_loss(desc); - mutex_unlock(&desc->plock); + mutex_unlock(&desc->lock); return 0; } -- 2.39.2