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From:   Szymon Janc <szymon.janc@codecoup.pl>
To:     Kai Krakow <kai@kaishome.de>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc:     "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 10:09:49 +0200
Message-ID: <4321662.LvFx2qVVIh@ix>
Organization: CODECOUP
In-Reply-To: <CABBYNZKBW1wtTbkmcQbAybGm7zdcur16935yGNwid9oiGOxNFQ@mail.gmail.com>
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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?


-- 
pozdrawiam
Szymon Janc