From 42cb967fd01b1f50374fdfa811f86db103eea532 Mon Sep 17 00:00:00 2001 From: Pete Zaitcev Date: Tue, 14 Aug 2007 13:19:16 -0700 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/usblp.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c index 3a0f8186d4bf..ad632f2d6f94 100644 --- a/drivers/usb/class/usblp.c +++ b/drivers/usb/class/usblp.c @@ -686,10 +686,30 @@ done: 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 @@ raise_badaddr: 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); -- 2.39.5