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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Wed, 12 May 2021 11:13:19 -0700
Message-ID: <CABBYNZKBW1wtTbkmcQbAybGm7zdcur16935yGNwid9oiGOxNFQ@mail.gmail.com>
Subject: Re: [PATCH] Bluetooth: Remove spurious error message
To:     Kai Krakow <kai@kaishome.de>
Cc:     Szymon Janc <szymon.janc@codecoup.pl>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        stable@vger.kernel.org
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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.


-- 
Luiz Augusto von Dentz