Re: [2.4] "Fix" introduced in 2.4.27pre2 for bluetooth hci_usb race causes kernel hang
From: Marcel Holtmann (marcel_at_holtmann.org)
Date: 04/13/05
- Previous message: aeriksson_at_fastmail.fm: "Re: DVD writer and IDE support..."
- In reply to: Tomas Qgren?=: "Re: [2.4] "Fix" introduced in 2.4.27pre2 for bluetooth hci_usb race causes kernel hang"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
To: Tomas Qgren?= <stric@acc.umu.se> Date: Wed, 13 Apr 2005 23:28:09 +0200
Hi Tomas,
> > > I have noticed a problem with a race condition fix introduced in
> > > 2.4.27-pre2 that causes the kernel to hang when disconnecting a
> > > Bluetooth USB dongle or doing 'hciconfig hci0 down'. No message is
> > > printed, the kernel just doesn't respond anymore.
> > >
> > > Seen in Changelog:
> > > Marcel Holtmann:
> > > o [Bluetooth] Fix race in RX complete routine of the USB drivers
> > >
> > > Reversing the following patch to hci_usb_rx_complete() makes 2.4.27-pre2
> > > up until 2.4.30 happy and does not hang when removing the dongle
> > > anymore. (bfusb.c has the same patch applied)
> > >
> > > 2.6.11.7 does not show the same problem, but has similar code to the
> > > "fixed" (that hangs) code in 2.4, so the real problem is probably
> > > somewhere else.
> >
> > does the attached patch makes any difference?
>
> It works just fine with pristine 2.4.30 and this patch. No deadlocks
> anymore.
if this works then we should do the same change in the bfusb driver. A
patch that fixes both drivers is attached.
Regards
Marcel
===== drivers/bluetooth/bfusb.c 1.3 vs edited =====
--- 1.3/drivers/bluetooth/bfusb.c 2004-04-16 14:01:40 +02:00
+++ edited/drivers/bluetooth/bfusb.c 2005-04-13 12:49:55 +02:00
@@ -470,11 +470,10 @@
return 0;
write_lock_irqsave(&bfusb->lock, flags);
+ write_unlock_irqrestore(&bfusb->lock, flags);
bfusb_unlink_urbs(bfusb);
bfusb_flush(hdev);
-
- write_unlock_irqrestore(&bfusb->lock, flags);
MOD_DEC_USE_COUNT;
===== drivers/bluetooth/hci_usb.c 1.23 vs edited =====
--- 1.23/drivers/bluetooth/hci_usb.c 2004-07-31 13:02:43 +02:00
+++ edited/drivers/bluetooth/hci_usb.c 2005-04-09 15:37:12 +02:00
@@ -398,12 +398,12 @@
BT_DBG("%s", hdev->name);
+ /* Synchronize with completion handlers */
write_lock_irqsave(&husb->completion_lock, flags);
-
+ write_unlock_irqrestore(&husb->completion_lock, flags);
+
hci_usb_unlink_urbs(husb);
hci_usb_flush(hdev);
-
- write_unlock_irqrestore(&husb->completion_lock, flags);
MOD_DEC_USE_COUNT;
return 0;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
- Previous message: aeriksson_at_fastmail.fm: "Re: DVD writer and IDE support..."
- In reply to: Tomas Qgren?=: "Re: [2.4] "Fix" introduced in 2.4.27pre2 for bluetooth hci_usb race causes kernel hang"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
|
