From: Oliver Neukum <oneukum@xxxxxxxx>
commit 2ca359f4f8b954b3a9d15a89f22a8b7283e7669f upstream.
This reverts commit d710734b06770814de2bfa2819420fb5df7f3a81.
This simplification causes a deadlock.
Reported-by: syzbot+7bbcbe9c9ff0cd49592a@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: d710734b0677 ("USB: rio500: simplify locking")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Link: https://lore.kernel.org/r/20190808092854.23519-1-oneukum@xxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/misc/rio500.c | 43 +++++++++++++++++++++++++++----------------
1 file changed, 27 insertions(+), 16 deletions(-)
--- a/drivers/usb/misc/rio500.c
+++ b/drivers/usb/misc/rio500.c
@@ -51,6 +51,7 @@ struct rio_usb_data {
char *obuf, *ibuf; /* transfer buffers */
char bulk_in_ep, bulk_out_ep; /* Endpoint assignments */
wait_queue_head_t wait_q; /* for timeouts */
+ struct mutex lock; /* general race avoidance */
};
static DEFINE_MUTEX(rio500_mutex);
@@ -62,8 +63,10 @@ static int open_rio(struct inode *inode,
/* against disconnect() */
mutex_lock(&rio500_mutex);
+ mutex_lock(&(rio->lock));
if (rio->isopen || !rio->present) {
+ mutex_unlock(&(rio->lock));
mutex_unlock(&rio500_mutex);
return -EBUSY;
}
@@ -71,6 +74,7 @@ static int open_rio(struct inode *inode,
init_waitqueue_head(&rio->wait_q);
+ mutex_unlock(&(rio->lock));
dev_info(&rio->rio_dev->dev, "Rio opened.\n");
mutex_unlock(&rio500_mutex);
@@ -84,6 +88,7 @@ static int close_rio(struct inode *inode
/* against disconnect() */
mutex_lock(&rio500_mutex);
+ mutex_lock(&(rio->lock));
rio->isopen = 0;
if (!rio->present) {
@@ -95,6 +100,7 @@ static int close_rio(struct inode *inode
} else {
dev_info(&rio->rio_dev->dev, "Rio closed.\n");
}
+ mutex_unlock(&(rio->lock));
mutex_unlock(&rio500_mutex);
return 0;
}
@@ -109,7 +115,7 @@ static long ioctl_rio(struct file *file,
int retries;
int retval=0;
- mutex_lock(&rio500_mutex);
+ mutex_lock(&(rio->lock));
/* Sanity check to make sure rio is connected, powered, etc */
if (rio->present == 0 || rio->rio_dev == NULL) {
retval = -ENODEV;
@@ -253,7 +259,7 @@ static long ioctl_rio(struct file *file,
err_out:
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return retval;
}
@@ -273,12 +279,12 @@ write_rio(struct file *file, const char
int errn = 0;
int intr;
- intr = mutex_lock_interruptible(&rio500_mutex);
+ intr = mutex_lock_interruptible(&(rio->lock));
if (intr)
return -EINTR;
/* Sanity check to make sure rio is connected, powered, etc */
if (rio->present == 0 || rio->rio_dev == NULL) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return -ENODEV;
}
@@ -301,7 +307,7 @@ write_rio(struct file *file, const char
goto error;
}
if (signal_pending(current)) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return bytes_written ? bytes_written : -EINTR;
}
@@ -339,12 +345,12 @@ write_rio(struct file *file, const char
buffer += copy_size;
} while (count > 0);
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return bytes_written ? bytes_written : -EIO;
error:
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return errn;
}
@@ -361,12 +367,12 @@ read_rio(struct file *file, char __user
char *ibuf;
int intr;
- intr = mutex_lock_interruptible(&rio500_mutex);
+ intr = mutex_lock_interruptible(&(rio->lock));
if (intr)
return -EINTR;
/* Sanity check to make sure rio is connected, powered, etc */
if (rio->present == 0 || rio->rio_dev == NULL) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return -ENODEV;
}
@@ -377,11 +383,11 @@ read_rio(struct file *file, char __user
while (count > 0) {
if (signal_pending(current)) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return read_count ? read_count : -EINTR;
}
if (!rio->rio_dev) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return -ENODEV;
}
this_read = (count >= IBUF_SIZE) ? IBUF_SIZE : count;
@@ -399,7 +405,7 @@ read_rio(struct file *file, char __user
count = this_read = partial;
} else if (result == -ETIMEDOUT || result == 15) { /* FIXME: 15 ??? */
if (!maxretry--) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
dev_err(&rio->rio_dev->dev,
"read_rio: maxretry timeout\n");
return -ETIME;
@@ -409,19 +415,19 @@ read_rio(struct file *file, char __user
finish_wait(&rio->wait_q, &wait);
continue;
} else if (result != -EREMOTEIO) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
dev_err(&rio->rio_dev->dev,
"Read Whoops - result:%d partial:%u this_read:%u\n",
result, partial, this_read);
return -EIO;
} else {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return (0);
}
if (this_read) {
if (copy_to_user(buffer, ibuf, this_read)) {
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return -EFAULT;
}
count -= this_read;
@@ -429,7 +435,7 @@ read_rio(struct file *file, char __user
buffer += this_read;
}
}
- mutex_unlock(&rio500_mutex);
+ mutex_unlock(&(rio->lock));
return read_count;
}
@@ -494,6 +500,8 @@ static int probe_rio(struct usb_interfac
}
dev_dbg(&intf->dev, "ibuf address:%p\n", rio->ibuf);
+ mutex_init(&(rio->lock));
+
usb_set_intfdata (intf, rio);
rio->present = 1;
bail_out:
@@ -511,10 +519,12 @@ static void disconnect_rio(struct usb_in
if (rio) {
usb_deregister_dev(intf, &usb_rio_class);
+ mutex_lock(&(rio->lock));
if (rio->isopen) {
rio->isopen = 0;
/* better let it finish - the release will do whats needed */
rio->rio_dev = NULL;
+ mutex_unlock(&(rio->lock));
mutex_unlock(&rio500_mutex);
return;
}
@@ -524,6 +534,7 @@ static void disconnect_rio(struct usb_in
dev_info(&intf->dev, "USB Rio disconnected.\n");
rio->present = 0;
+ mutex_unlock(&(rio->lock));
}
mutex_unlock(&rio500_mutex);
}
