Re: [2.4] "Fix" introduced in 2.4.27pre2 for bluetooth hci_usb race causes kernel hang

[Tomas Ögren <stric@acc.umu.se>]

On 09 April, 2005 - Marcel Holtmann sent me these 1,6K bytes:

> 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.

/Tomas
-- 
Tomas Ögren, stric@acc.umu.se, http://www.acc.umu.se/~stric/
|- Student at Computing Science, University of Umeå
`- Sysadmin at {cs,acc}.umu.se
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