On Fri, May 21, 2021 at 08:24:58PM +0800, 慕冬亮 wrote:

On Fri, May 21, 2021 at 8:18 PM Greg KH [off-list ref] wrote:

quoted

On Fri, May 21, 2021 at 08:08:11PM +0800, Dongliang Mu wrote:

quoted

r871xu_dev_remove failed to call r8712_free_drv_sw() and free the
resource (e.g., struct urb) due to the failure of firmware loading.

Fix this by invoking r8712_free_drv_sw at the failure site.

Reported-by: syzbot+1c46f3771695bccbdb3a@syzkaller.appspotmail.com
Fixes: b4383c971bc5 ("staging: rtl8712: handle firmware load failure")
Signed-off-by: Dongliang Mu <redacted>
---
 drivers/staging/rtl8712/usb_intf.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
index dc21e7743349..a5190b4250ce 100644
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c

@@ -589,7 +589,7 @@ static int r871xu_drv_init(struct usb_interface *pusb_intf,
  */
 static void r871xu_dev_remove(struct usb_interface *pusb_intf)
 {
-     struct net_device *pnetdev = usb_get_intfdata(pusb_intf);
+     struct net_device *pnetdev, *newpnetdev = usb_get_intfdata(pusb_intf);
      struct usb_device *udev = interface_to_usbdev(pusb_intf);

      if (pnetdev) {

Did you test this?

For now, I only tested this patch in my local workspace. The memory
leak does not occur any more.

I have pushed a patch testing onto the syzbot dashboard [1]. Now it is
in the pending state.

[1] https://syzkaller.appspot.com/bug?id=3a325b8389fc41c1bc94de0f4ac437ed13cce584

quoted

I think you just broke the code right here :(

If I broke any code logic, I am sorry. However, this patch only adds
some code to deallocate some resources when failing to load firmware.

Do you mean that I replace pnetdev with the variable - newpnetdev?

Yes, and then the first thing the code does is check the value of
pnetdev which is totally undefined :(