Re: [PATCH net] net: qmi_wwan: fix Oops while disconnecting
From: Bjørn Mork <hidden>
Date: 2012-06-28 08:36:49
Bjørn Mork [off-list ref] writes: [..]
Fixes this Oops where a cdc-wdm device was closed while the USB device was disconnecting, causing wdm_release to call qmi_wwan_cdc_wdm_manage_power after intfdata was set to NULL by usbnet_disconnect: [41819.087460] BUG: unable to handle kernel NULL pointer dereference at 00000080 [41819.087815] IP: [<f8640458>] qmi_wwan_manage_power+0x68/0x90 [qmi_wwan] [41819.088028] *pdpt = 000000000314f001 *pde = 0000000000000000 [41819.088028] Oops: 0002 [#1] SMP
[..]
quoted hunk
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c index 3767a12..b01960f 100644 --- a/drivers/net/usb/qmi_wwan.c +++ b/drivers/net/usb/qmi_wwan.c@@ -197,6 +197,10 @@ err: static int qmi_wwan_cdc_wdm_manage_power(struct usb_interface *intf, int on) { struct usbnet *dev = usb_get_intfdata(intf); + + /* can be called while disconnecting */ + if (!dev) + return 0; return qmi_wwan_manage_power(dev, on); }
Hello, I'd like this patch applied to qmi_wwan regardless of the outcome of the (now stalled?) generic usbnet_disconnect discussion. The patch fixes a real Oops in 3.4 and 3.5, and I believe it should be left in qmi_wwan even if the usbnet code is fixed to avoid this specific bug. The additional NULL test won't harm, and it makes the code more robust should someone decide to rearrange usbnet_disconnect again at some later point in time. I really want this fixed in the next 3.4 stable release, if possible. Should I resubmit the patch, or will you pick it up from http://patchwork.ozlabs.org/patch/166542/ ? Thanks, Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html