>From 6dd0092cdb010a5dadc94809a63ff4f5240ed5c8 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@xxxxxxxxxx>
Date: Tue, 9 Feb 2010 16:40:27 +0100
Subject: [PATCH 1/6] 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 <neukum@xxxxxxxxxxxxx>
---
drivers/usb/class/cdc-wdm.c | 84 +++++++++++++++++++++++--------------------
1 files changed, 45 insertions(+), 39 deletions(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 3e564bf..e1d6b82 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;
}
--
1.6.4.2
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