[PATCH 5.4 15/67] staging: rtl8712: handle firmware load failure

Greg Kroah-Hartman
2020-08-10T15:37:56Z

From: Rustam Kovhaev <rkovhaev@gmail.com>

commit b4383c971bc5263efe2b0915ba67ebf2bf3f1ee5 upstream.

when firmware fails to load we should not call unregister_netdev()
this patch fixes a race condition between rtl871x_load_fw_cb() and
r871xu_dev_remove() and fixes the bug reported by syzbot

Reported-by: syzbot+80899a8a8efe8968cde7@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=80899a8a8efe8968cde7
Signed-off-by: Rustam Kovhaev <rkovhaev@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200716151324.1036204-1-rkovhaev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/staging/rtl8712/hal_init.c | 3 ++-
drivers/staging/rtl8712/usb_intf.c | 11 ++++++++---
2 files changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -33,7 +33,6 @@ static void rtl871x_load_fw_cb(const str
{
struct _adapter *adapter = context;

- complete(&adapter->rtl8712_fw_ready);
if (!firmware) {
struct usb_device *udev = adapter->dvobjpriv.pusbdev;
struct usb_interface *usb_intf = adapter->pusb_intf;
@@ -41,11 +40,13 @@ static void rtl871x_load_fw_cb(const str
dev_err(&udev->dev, "r8712u: Firmware request failed\n");
usb_put_dev(udev);
usb_set_intfdata(usb_intf, NULL);
+ complete(&adapter->rtl8712_fw_ready);
return;
}
adapter->fw = firmware;
/* firmware available - start netdev */
register_netdev(adapter->pnetdev);
+ complete(&adapter->rtl8712_fw_ready);
}

static const char firmware_file[] = "rtlwifi/rtl8712u.bin";
--- a/drivers/staging/rtl8712/usb_intf.c
+++ b/drivers/staging/rtl8712/usb_intf.c
@@ -595,13 +595,17 @@ static void r871xu_dev_remove(struct usb
if (pnetdev) {
struct _adapter *padapter = netdev_priv(pnetdev);

- usb_set_intfdata(pusb_intf, NULL);
- release_firmware(padapter->fw);
/* never exit with a firmware callback pending */
wait_for_completion(&padapter->rtl8712_fw_ready);
+ pnetdev = usb_get_intfdata(pusb_intf);
+ usb_set_intfdata(pusb_intf, NULL);
+ if (!pnetdev)
+ goto firmware_load_fail;
+ release_firmware(padapter->fw);
if (drvpriv.drv_registered)
padapter->surprise_removed = true;
- unregister_netdev(pnetdev); /* will call netdev_close() */
+ if (pnetdev->reg_state != NETREG_UNINITIALIZED)
+ unregister_netdev(pnetdev); /* will call netdev_close() */
flush_scheduled_work();
udelay(1);
/* Stop driver mlme relation timer */
@@ -614,6 +618,7 @@ static void r871xu_dev_remove(struct usb
*/
usb_put_dev(udev);
}
+firmware_load_fail:
/* If we didn't unplug usb dongle and remove/insert module, driver
* fails on sitesurvey for the first time when device is up.
* Reset usb port for sitesurvey fail issue.