From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank.Li@freescale.com (Frank Li) Date: Tue, 5 Feb 2013 14:26:17 +0800 Subject: [PATCH v2 2/2 net-next] net: fec: fix spin_lock dead lock In-Reply-To: <1360045577-6266-1-git-send-email-Frank.Li@freescale.com> References: <1360045577-6266-1-git-send-email-Frank.Li@freescale.com> Message-ID: <1360045577-6266-2-git-send-email-Frank.Li@freescale.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org ========================================================= [ 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 --- * fix new problem report by Jim 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