From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Wang Subject: Re: [PATCH] Bluetooth: mediatek: fix uninitialized symbol errors in btmtksdio_rx_packet Date: Tue, 19 Mar 2019 02:02:31 +0800 Message-ID: <1552932151.24944.12.camel@mtkswgap22> References: <8fb8e6840a39127112597963d665fbe6c21d8b91.1552509647.git.sean.wang@mediatek.com> <93CB6259-6FB8-4D3D-9FF3-8EB59499A6A1@holtmann.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <93CB6259-6FB8-4D3D-9FF3-8EB59499A6A1@holtmann.org> Sender: linux-kernel-owner@vger.kernel.org To: Marcel Holtmann Cc: Johan Hedberg , linux-bluetooth@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: linux-mediatek@lists.infradead.org On Mon, 2019-03-18 at 17:55 +0100, Marcel Holtmann wrote: > Hi Sean, > > > Fixed all the below warnings. They would probably cause the following > > error handling path would use the uninitialized value and then produce > > unexpected behavior. > > > > drivers/bluetooth/btmtksdio.c:470:2: warning: ‘old_len’ may be used > > uninitialized in this function [-Wmaybe-uninitialized] > > print_hex_dump(KERN_ERR, "err sdio rx: ", DUMP_PREFIX_NONE, 4, 1, > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > old_data, old_len, true); > > ~~~~~~~~~~~~~~~~~~~~~~~~ > > drivers/bluetooth/btmtksdio.c:376:15: note: ‘old_len’ was declared here > > unsigned int old_len; > > ^~~~~~~ > > drivers/bluetooth/btmtksdio.c:470:2: warning: ‘old_data’ may be used > > uninitialized in this function [-Wmaybe-uninitialized] > > print_hex_dump(KERN_ERR, "err sdio rx: ", DUMP_PREFIX_NONE, 4, 1, > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > old_data, old_len, true); > > ~~~~~~~~~~~~~~~~~~~~~~~~ > > drivers/bluetooth/btmtksdio.c:375:17: note: ‘old_data’ was declared here > > unsigned char *old_data; > > ^~~~~~~~ > > > > Fixes: d74eef2834b5 ("Bluetooth: mediatek: add support for MediaTek MT7663S and MT7668S SDIO devices") > > Reported-by: Dan Carpenter > > Reported-by: Marcel Holtmann > > Signed-off-by: Sean Wang > > --- > > drivers/bluetooth/btmtksdio.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c > > index b4b8320f279e..23cf63888bac 100644 > > --- a/drivers/bluetooth/btmtksdio.c > > +++ b/drivers/bluetooth/btmtksdio.c > > @@ -372,8 +372,8 @@ static int btmtksdio_rx_packet(struct btmtksdio_dev *bdev, u16 rx_size) > > const struct h4_recv_pkt *pkts = mtk_recv_pkts; > > int pkts_count = ARRAY_SIZE(mtk_recv_pkts); > > struct mtkbtsdio_hdr *sdio_hdr; > > - unsigned char *old_data; > > - unsigned int old_len; > > + unsigned char *old_data = NULL; > > + unsigned int old_len = 0; > > int err, i, pad_size; > > struct sk_buff *skb; > > u16 dlen; > > or instead just remove this whole old_len + old_data stuff anyway since it is rather pointless. Or at least introduce a proper error path for sdio_readsb since you know when it fails, there is no point in writing the SKB. > > Regards > I will remove the old_len and old_data in the next version for the issue because the error path for sdio_readsb seems wrong. My initial purpose is that I would like to add a error path for these packets which are successful at sdio_readsb but fail at packet format parsing. I will update the error path for packet format error in a separate patch. > Marcel >