Hi Marcel,

On Wed, Mar 07, 2012 at 11:33:17AM -0800, Marcel Holtmann wrote:

Hi Johan,

quoted

Do not close protocol driver until device has been unregistered.

This fixes a race between tty_close and hci_dev_open which can result in
a NULL-pointer dereference.

The line discipline closes the protocol driver while we may still have
hci_dev_open sleeping on the req_lock mutex resulting in a NULL-pointer
dereference when lock is acquired and hci_init_req called.

[...]

what kernel version is this against? Our changes in bluetooth-next fixed
some of the destruct handling.

This is against the latest rc as it needs to be fixed in 3.3, but I
missed a dependency to bluetooth-next as you point out below.

Also hci_unregister_dev should be calling the destruct handler and thus
your change is now accessing hu but it got freed already.

You're right, my patch depends on 010666a126fc ("Bluetooth: Make
hci-destruct callback optional") and 797fe796c4 ("Bluetooth: uart-ldisc:
Fix memory leak and remove destruct cb") from bluetooth-next. 

But since the latter one fixes a memory leak it should have been marked
for stable as well as pushed to Linus for 3.3, right?

Thanks,
Johan