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Date: Thu, 4 Jan 2024 17:41:12 +0000
From: Simon Horman <horms@kernel.org>
To: Jonas =?utf-8?Q?Dre=C3=9Fler?= <verdre@v0yd.nl>
Cc: Marcel Holtmann <marcel@holtmann.org>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
	linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH] Bluetooth: hci_sync: Check the correct flag before
 starting a scan
Message-ID: <20240104174112.GJ31813@kernel.org>
References: <20240102180810.54515-1-verdre@v0yd.nl>
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In-Reply-To: <20240102180810.54515-1-verdre@v0yd.nl>

On Tue, Jan 02, 2024 at 07:08:08PM +0100, Jonas Dreßler wrote:
> There's a very confusing mistake in the code starting a HCI inquiry: We're
> calling hci_dev_test_flag() to test for HCI_INQUIRY, but hci_dev_test_flag()
> checks hdev->dev_flags instead of hdev->flags. HCI_INQUIRY is a bit that's
> set on hdev->flags, not on hdev->dev_flags though.
> 
> HCI_INQUIRY equals the integer 7, and in hdev->dev_flags, 7 means
> HCI_BONDABLE, so we were actually checking for HCI_BONDABLE here.
> 
> The mistake is only present in the synchronous code for starting an inquiry,
> not in the async one. Also devices are typically bondable while doing an
> inquiry, so that might be the reason why nobody noticed it so far.
> 
> Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>

FWIIW, I agree with this analysis and the proposed fix looks
correct to me.

Reviewed-by: Simon Horman <horms@kernel.org>

I do wonder if it is appropriate to treat this as a bug fix -
is there a use-visible problem? If so, the following seems appropriate to
me.

Fixes: abfeea476c68 ("Bluetooth: hci_sync: Convert MGMT_OP_START_DISCOVERY")

...