usblp: Fix a double kfree
If submit fails, slab hits a BUG() because of a double kfree.
The today's lesson is, you cannot just slap USB_FREE_BUFFER on code
without adjusting the error paths.
The patch is made bigger by opportunistic refactoring.
Signed-Off-By: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index 3a0f818..ad632f2 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -686,10 +686,30 @@
return retval;
}
+static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
+{
+ struct urb *urb;
+ char *writebuf;
+
+ if ((writebuf = kmalloc(transfer_length, GFP_KERNEL)) == NULL)
+ return NULL;
+ if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL) {
+ kfree(writebuf);
+ return NULL;
+ }
+
+ usb_fill_bulk_urb(urb, usblp->dev,
+ usb_sndbulkpipe(usblp->dev,
+ usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
+ writebuf, transfer_length, usblp_bulk_write, usblp);
+ urb->transfer_flags |= URB_FREE_BUFFER;
+
+ return urb;
+}
+
static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
struct usblp *usblp = file->private_data;
- char *writebuf;
struct urb *writeurb;
int rv;
int transfer_length;
@@ -710,18 +730,11 @@
transfer_length = USBLP_BUF_SIZE;
rv = -ENOMEM;
- if ((writebuf = kmalloc(USBLP_BUF_SIZE, GFP_KERNEL)) == NULL)
- goto raise_buf;
- if ((writeurb = usb_alloc_urb(0, GFP_KERNEL)) == NULL)
+ if ((writeurb = usblp_new_writeurb(usblp, transfer_length)) == NULL)
goto raise_urb;
- usb_fill_bulk_urb(writeurb, usblp->dev,
- usb_sndbulkpipe(usblp->dev,
- usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
- writebuf, transfer_length, usblp_bulk_write, usblp);
- writeurb->transfer_flags |= URB_FREE_BUFFER;
usb_anchor_urb(writeurb, &usblp->urbs);
- if (copy_from_user(writebuf,
+ if (copy_from_user(writeurb->transfer_buffer,
buffer + writecount, transfer_length)) {
rv = -EFAULT;
goto raise_badaddr;
@@ -780,8 +793,6 @@
usb_unanchor_urb(writeurb);
usb_free_urb(writeurb);
raise_urb:
- kfree(writebuf);
-raise_buf:
raise_wait:
collect_error: /* Out of raise sequence */
mutex_unlock(&usblp->wmut);