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From:   Szymon Janc <szymon.janc@codecoup.pl>
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     Kai Krakow <kai@kaishome.de>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        stable@vger.kernel.org
Subject: Re: [PATCH] Bluetooth: Remove spurious error message
Date:   Thu, 13 May 2021 14:23:26 +0200
Message-ID: <4628749.GXAFRqVoOG@ix>
Organization: CODECOUP
In-Reply-To: <YJz8hJ+9N24wrIsq@kroah.com>
References: <20210512133407.52330-1-szymon.janc@codecoup.pl> <4321662.LvFx2qVVIh@ix> <YJz8hJ+9N24wrIsq@kroah.com>
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Hi,

On Thursday, 13 May 2021 12:16:36 CEST Greg KH wrote:
> On Thu, May 13, 2021 at 10:09:49AM +0200, Szymon Janc wrote:
> > Hi,
> > 
> > On Wednesday, 12 May 2021 20:13:19 CEST Luiz Augusto von Dentz wrote:
> > > Hi Kai,
> > > 
> > > On Wed, May 12, 2021 at 11:06 AM Kai Krakow <kai@kaishome.de> wrote:
> > > > Hi Szymon!
> > > > 
> > > > Am Mi., 12. Mai 2021 um 15:34 Uhr schrieb Szymon Janc
> > 
> > <szymon.janc@codecoup.pl>:
> > > > > Even with rate limited reporting this is very spammy and since
> > > > > it is remote device that is providing bogus data there is no
> > > > > need to report this as error.
> > > > 
> > > > [...]
> > > > 
> > > > > [72464.546319] Bluetooth: hci0: advertising data len corrected
> > > > > [72464.857318] Bluetooth: hci0: advertising data len corrected
> > > > > [72465.163332] Bluetooth: hci0: advertising data len corrected
> > > > > [72465.278331] Bluetooth: hci0: advertising data len corrected
> > > > > [72465.432323] Bluetooth: hci0: advertising data len corrected
> > > > > [72465.891334] Bluetooth: hci0: advertising data len corrected
> > > > > [72466.045334] Bluetooth: hci0: advertising data len corrected
> > > > > [72466.197321] Bluetooth: hci0: advertising data len corrected
> > > > > [72466.340318] Bluetooth: hci0: advertising data len corrected
> > > > > [72466.498335] Bluetooth: hci0: advertising data len corrected
> > > > > [72469.803299] bt_err_ratelimited: 10 callbacks suppressed
> > > > > 
> > > > > Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
> > > > > Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=203753
> > > > > Cc: stable@vger.kernel.org
> > > > > ---
> > > > > 
> > > > >  net/bluetooth/hci_event.c | 2 --
> > > > >  1 file changed, 2 deletions(-)
> > > > > 
> > > > > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> > > > > index 5e99968939ce..abdc44dc0b2f 100644
> > > > > --- a/net/bluetooth/hci_event.c
> > > > > +++ b/net/bluetooth/hci_event.c
> > > > > @@ -5476,8 +5476,6 @@ static void process_adv_report(struct hci_dev
> > > > > *hdev, u8 type, bdaddr_t *bdaddr,> >
> > > > > 
> > > > >         /* Adjust for actual length */
> > > > >         if (len != real_len) {
> > > > > 
> > > > > -               bt_dev_err_ratelimited(hdev, "advertising data len
> > > > > corrected %u -> %u", -                                      len,
> > > > > real_len);
> > > > > 
> > > > >                 len = real_len;
> > > > >         
> > > > >         }
> > > > 
> > > > This renders the "if" quite useless since it now always ensures len =
> > > > real_len and nothing else. At this point, the "if" can be removed, and
> > > > len can be set unconditionally. Depending on the further context of
> > > > the patch, destinction between real_len and len may not be needed at
> > > > all and real_len could be renamed to len, ditching the unused original
> > > > which is potentially bogus data anyways according to your commit
> > > > description.
> > > 
> > > That was introduced to truncate the len, the patch just removes the
> > > logging but it does keep this logic, if you want to understand the
> > > reason for it just use git blame and look at the history.
> > 
> > Actually, with no log there is no need for this "if" and real_len could be
> > indeed avoided.
> > 
> > But I'd change this is subsequent patch which would not be tagged as
> > stable
> > candidate. Thoughts?
> 
> Fix it properly, and worry about stable trees later, they can also
> always take the correct change as well.

Fair enough, V2 sent.

-- 
pozdrawiam
Szymon Janc