From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Li Subject: [PATCH v3 2/2 net-next] net: fec: fix spin_lock dead lock Date: Thu, 7 Feb 2013 08:59:59 +0800 Message-ID: <1360198799-25173-2-git-send-email-Frank.Li@freescale.com> References: <1360198799-25173-1-git-send-email-Frank.Li@freescale.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , Frank Li To: , , , Return-path: Received: from ch1ehsobe003.messaging.microsoft.com ([216.32.181.183]:14783 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752296Ab3BGBh0 (ORCPT ); Wed, 6 Feb 2013 20:37:26 -0500 In-Reply-To: <1360198799-25173-1-git-send-email-Frank.Li@freescale.com> Sender: netdev-owner@vger.kernel.org List-ID: ========================================================= [ INFO: possible irq lock inversion dependency detected ] 3.8.0-rc5+ #82 Not tainted --------------------------------------------------------- swapper/0/0 just changed the state of lock: (&(&fep->hw_lock)->rlock){..-...}, at: [<8034e2f8>] fec_enet_start_xmit+0x48/0x 2cc but this lock took another, SOFTIRQ-unsafe lock in the past: (prepare_lock){+.+.+.} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(prepare_lock); local_irq_disable() lock(&(&fep->hw_lock)->rlock); lock(prepare_lock); lock(&(&fep->hw_lock)->rlock); *** DEADLOCK *** Signed-off-by: Frank Li --- No change from v1 to v3. drivers/net/ethernet/freescale/fec_ptp.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c index c40526c..1f17ca0 100644 --- a/drivers/net/ethernet/freescale/fec_ptp.c +++ b/drivers/net/ethernet/freescale/fec_ptp.c @@ -104,7 +104,7 @@ void fec_ptp_start_cyclecounter(struct net_device *ndev) unsigned long flags; int inc; - inc = 1000000000 / clk_get_rate(fep->clk_ptp); + inc = 1000000000 / fep->cycle_speed; /* grab the ptp lock */ spin_lock_irqsave(&fep->tmreg_lock, flags); @@ -363,6 +363,8 @@ void fec_ptp_init(struct net_device *ndev, struct platform_device *pdev) fep->ptp_caps.settime = fec_ptp_settime; fep->ptp_caps.enable = fec_ptp_enable; + fep->cycle_speed = clk_get_rate(fep->clk_ptp); + spin_lock_init(&fep->tmreg_lock); fec_ptp_start_cyclecounter(ndev); -- 1.7.1