From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933490AbcHUPh7 (ORCPT ); Sun, 21 Aug 2016 11:37:59 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:55996 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933170AbcHUPh4 (ORCPT ); Sun, 21 Aug 2016 11:37:56 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Wolfgang Grandegger , Marc Kleine-Budde , Willy Tarreau Subject: [PATCH 3.10 148/180] can: at91_can: RX queue could get stuck at high bus load Date: Sun, 21 Aug 2016 17:31:18 +0200 Message-Id: <1471793510-13022-149-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1471793510-13022-1-git-send-email-w@1wt.eu> References: <1471793510-13022-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wolfgang Grandegger commit 43200a4480cbbe660309621817f54cbb93907108 upstream. At high bus load it could happen that "at91_poll()" enters with all RX message boxes filled up. If then at the end the "quota" is exceeded as well, "rx_next" will not be reset to the first RX mailbox and hence the interrupts remain disabled. Signed-off-by: Wolfgang Grandegger Tested-by: Amr Bekhit Cc: Signed-off-by: Marc Kleine-Budde Signed-off-by: Willy Tarreau --- drivers/net/can/at91_can.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c index 535d5dd..024078c 100644 --- a/drivers/net/can/at91_can.c +++ b/drivers/net/can/at91_can.c @@ -731,9 +731,10 @@ static int at91_poll_rx(struct net_device *dev, int quota) /* upper group completed, look again in lower */ if (priv->rx_next > get_mb_rx_low_last(priv) && - quota > 0 && mb > get_mb_rx_last(priv)) { + mb > get_mb_rx_last(priv)) { priv->rx_next = get_mb_rx_first(priv); - goto again; + if (quota > 0) + goto again; } return received; -- 2.8.0.rc2.1.gbe9624a