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usblp: Fix a double kfree

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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>
This commit is contained in:
Pete Zaitcev 2007-08-14 13:19:16 -07:00 committed by Greg Kroah-Hartman
parent c36d54ab38
commit 42cb967fd0
1 changed files with 23 additions and 12 deletions
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35
drivers/usb/class/usblp.c
View file

@ -686,10 +686,30 @@ static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t
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 @@ static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t
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);