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Date:   Mon, 18 Nov 2019 15:27:12 -0500
From:   Ralph Siemsen <ralph.siemsen@linaro.org>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        syzbot+899a33dc0fa0dbaf06a6@syzkaller.appspotmail.com,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Jeremy Cline <jcline@redhat.com>,
        Marcel Holtmann <marcel@holtmann.org>
Subject: Re: [PATCH 4.9 02/31] Bluetooth: hci_ldisc: Postpone
 HCI_UART_PROTO_READY bit set in hci_uart_set_proto()
Message-ID: <20191118202712.GA14832@maple.netwinder.org>
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 <20191116075614.GB381281@kroah.com>
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On Sat, Nov 16, 2019 at 03:56:14PM +0800, Greg Kroah-Hartman wrote:
>>
>> BTW, this also seems to be missing from 4.4 branch, although it was merged
>> for 3.16 (per https://lore.kernel.org/stable/?q=Postpone+HCI).
>
>Odd that it was merged into 3.16, perhaps it was done there because some
>earlier patch added the problem?

This patch should really be viewed as a correction to an earlier commit:
84cb3df02aea ("Bluetooth: hci_ldisc: Fix null pointer derefence in case 
of early data"). This was merged 2016-Apr-08 into v4.7, and therefore is 
included in 4.9 and higher.

Only very recently, on 2019-Sep-23, this was backported to 3.16, along 
with the correction. Both appeared in v3.16.74.

> I say this as I do not think this is
>relevant for the 4.4.y kernel, do you?  Have you tried to apply this
>patch there?

The patch does not apply, but this is mainly due to the earlier commit 
missing. It seems to me like that earlier fix is desirable (and it was 
put into 3.16), along with the followup. So I would think we want it in 
4.4 as well.

[Aside: I'm really only interested in 4.9 and 4.19, so the 4.4 stuff is 
just a diversion. But figured I might as well mention what I found...]

Regards,
-Ralph