From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2994346AbcBSWZ5 (ORCPT ); Fri, 19 Feb 2016 17:25:57 -0500 Received: from mail-pa0-f49.google.com ([209.85.220.49]:35159 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2994318AbcBSWZy (ORCPT ); Fri, 19 Feb 2016 17:25:54 -0500 From: Douglas Anderson To: Johan Hedberg , Marcel Holtmann Cc: Douglas Anderson , gustavo@padovan.org, johan.hedberg@gmail.com, davem@davemloft.net, linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] Bluetooth: hci_core: Avoid mixing up req_complete and req_complete_skb Date: Fri, 19 Feb 2016 14:25:21 -0800 Message-Id: <1455920722-20892-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.7.0.rc3.207.g0ac5344 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In commit 44d271377479 ("Bluetooth: Compress the size of struct hci_ctrl") we squashed down the size of the structure by using a union with the assumption that all users would use the flag to determine whether we had a req_complete or a req_complete_skb. Unfortunately we had a case in hci_req_cmd_complete() where we weren't looking at the flag. This can result in a situation where we might be storing a hci_req_complete_skb_t in a hci_req_complete_t variable, or vice versa. During some testing I found at least one case where the function hci_req_sync_complete() was called improperly because the kernel thought that it didn't require an SKB. Looking through the stack in kgdb I found that it was called by hci_event_packet() and that hci_event_packet() had both of its locals "req_complete" and "req_complete_skb" pointing to the same place: both to hci_req_sync_complete(). Let's make sure we always check the flag. For more details on debugging done, see . Fixes: 44d271377479 ("Bluetooth: Compress the size of struct hci_ctrl") Signed-off-by: Douglas Anderson --- Testing was done on a Chrome OS device on kernel 3.14 w/ bluetooth-next backports. Since I couldn't reliably reproduce the problem, I simply confirmed that existing functionality worked. net/bluetooth/hci_core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 541760fe53d4..9c0a6830ff92 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -4118,8 +4118,10 @@ void hci_req_cmd_complete(struct hci_dev *hdev, u16 opcode, u8 status, break; } - *req_complete = bt_cb(skb)->hci.req_complete; - *req_complete_skb = bt_cb(skb)->hci.req_complete_skb; + if (bt_cb(skb)->hci.req_flags & HCI_REQ_SKB) + *req_complete_skb = bt_cb(skb)->hci.req_complete_skb; + else + *req_complete = bt_cb(skb)->hci.req_complete; kfree_skb(skb); } spin_unlock_irqrestore(&hdev->cmd_q.lock, flags); -- 2.7.0.rc3.207.g0ac5344