Re: Bluetooth regression breaking BT connection for all 2.0 and older devices in 5.0.15+, 5.1.x and master

[Greg Kroah-Hartman]

On Mon, Jun 10, 2019 at 03:31:55PM +0200, Hans de Goede wrote:
> Hi All,
> 
> First of all this is a known issue and it seems a fix is in the works,
> but what I do not understand is why the commit causing this has not
> simply been reverted until the fix is done, esp. for the 5.0.x
> stable series where this was introduced in 5.0.15.
> 
> The problem I'm talking about is commit d5bb334a8e17 ("Bluetooth: Align
> minimum encryption key size for LE and BR/EDR connections"):
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d5bb334a8e171b262e48f378bd2096c0ea458265
> basically completely breaking all somewhat older (and some current cheap
> no-name) bluetooth devices:
> 
> A revert of this was first proposed on May 22nd:
> https://lore.kernel.org/netdev/CA+E=qVfopSA90vG2Kkh+XzdYdNn=M-hJN_AptW=R+B5v3HB9eA@xxxxxxxxxxxxxx/T/
> We are 18 days further now and this problem still exists, including in the
> 5.0.15+ and 5.1.x stable kernels.
> 
> A solution has been suggested: https://lore.kernel.org/linux-bluetooth/20190522070540.48895-1-marcel@xxxxxxxxxxxx/T/#u
> and at least the Fedora 5.1.4+ kernels now carry this as a temporary fix,
> but as of today I do not see a fix nor a revert in Torvald's tree yet and
> neither does there seem to be any fix in the 5.0.x and 5.1.x stable series.
> 
> In the mean time we are getting a lot of bug reports about this:
> https://bugzilla.kernel.org/show_bug.cgi?id=203643
> https://bugzilla.redhat.com/show_bug.cgi?id=1711468
> https://bugzilla.redhat.com/show_bug.cgi?id=1713871
> https://bugzilla.redhat.com/show_bug.cgi?id=1713980
> 
> And some reporters:
> https://bugzilla.redhat.com/show_bug.cgi?id=1713871#c4
> Are indicating that the Fedora kernels with the workaround included
> still do not work...
> 
> As such I would like to suggest that we just revert the troublesome
> commit for now and re-add it when we have a proper fix.

I agree, can someone revert this in Linus's tree so I can revert it in a
stable release?

thanks,

greg k-h