From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754224AbaJ0T1p (ORCPT ); Mon, 27 Oct 2014 15:27:45 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:52413 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752382AbaJ0S5m (ORCPT ); Mon, 27 Oct 2014 14:57:42 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Loic Poulain , Marcel Holtmann , Kamal Mostafa Subject: [PATCH 3.13 001/105] Bluetooth: Fix HCI H5 corrupted ack value Date: Mon, 27 Oct 2014 11:55:36 -0700 Message-Id: <1414436240-13879-2-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1414436240-13879-1-git-send-email-kamal@canonical.com> References: <1414436240-13879-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Loic Poulain commit 4807b51895dce8aa650ebebc51fa4a795ed6b8b8 upstream. In this expression: seq = (seq - 1) % 8 seq (u8) is implicitly converted to an int in the arithmetic operation. So if seq value is 0, operation is ((0 - 1) % 8) => (-1 % 8) => -1. The new seq value is 0xff which is an invalid ACK value, we expect 0x07. It leads to frequent dropped ACK and retransmission. Fix this by using '&' binary operator instead of '%'. Signed-off-by: Loic Poulain Signed-off-by: Marcel Holtmann Signed-off-by: Kamal Mostafa --- drivers/bluetooth/hci_h5.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c index e36a024..5651992 100644 --- a/drivers/bluetooth/hci_h5.c +++ b/drivers/bluetooth/hci_h5.c @@ -237,7 +237,7 @@ static void h5_pkt_cull(struct h5 *h5) break; to_remove--; - seq = (seq - 1) % 8; + seq = (seq - 1) & 0x07; } if (seq != h5->rx_ack) -- 1.9.1