diff mbox series

[net,1/2] net: fec_ptp: add clock rate zero check

Message ID 20210616091426.13694-2-qiangqing.zhang@nxp.com
State New
Headers show
Series [net,1/2] net: fec_ptp: add clock rate zero check | expand

Commit Message

Joakim Zhang June 16, 2021, 9:14 a.m. UTC 
From: Fugang Duan <fugang.duan@nxp.com>

Add clock rate zero check to fix coverity issue of "divide by 0".

Fixes: commit 85bd1798b24a ("net: fec: fix spin_lock dead lock")
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
---
 drivers/net/ethernet/freescale/fec_ptp.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Russell King (Oracle) June 16, 2021, 1:28 p.m. UTC | #1 
Hi Joakim,

On Wed, Jun 16, 2021 at 11:40:29AM +0000, Joakim Zhang wrote:
> Do you mean that print an error message then return directly? It seems better.

Nearly - one has to ensure that the cleanup functions don't provoke a
crash though. I notice fec_ptp_stop() makes use of fep->time_keep
and also fep->ptp_clock.

fep->time_keep is initialised after where you need to test for zero
cycle_speed, so the initialisation would need moving earlier.

I would have thought that ftp->ptp_clock should be NULL, so that's
probably okay, but should be checked that this assumption is in fact
true.

> if (!fep->cycle_speed) {
> 	dev_err(&fep->pdev->dev, "PTP clock rate should not be zero!\n");

I'd still say something like "PTP clock rate should not be zero,
disabling PTP" - say what's wrong and what we are doing. Also,
please avoid exclaimation marks in error messages.

Thanks.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c
index 1753807cbf97..7326a0612823 100644
--- a/drivers/net/ethernet/freescale/fec_ptp.c
+++ b/drivers/net/ethernet/freescale/fec_ptp.c
@@ -604,6 +604,10 @@  void fec_ptp_init(struct platform_device *pdev, int irq_idx)
 	fep->ptp_caps.enable = fec_ptp_enable;
 
 	fep->cycle_speed = clk_get_rate(fep->clk_ptp);
+	if (!fep->cycle_speed) {
+		fep->cycle_speed = NSEC_PER_SEC;
+		dev_err(&fep->pdev->dev, "clk_ptp clock rate is zero\n");
+	}
 	fep->ptp_inc = NSEC_PER_SEC / fep->cycle_speed;
 
 	spin_lock_init(&fep->tmreg_lock);