[PATCH 6.12 343/403] net: ravb: avoid dereferencing an invalid PTP clock
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2026-09-04 06:20:24
Also in:
linux-patches
6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xuanqiang Luo <redacted>
commit 1f77af0aaf277413ff32f6ff8c2c4282bd64c897 upstream.
The PTP clock is unavailable before the first open, so querying its
index can dereference a NULL pointer. Registration failures can also
leave an error pointer in priv->ptp.clock.
Cache the PHC index separately and report -1 while no clock is
registered. Normalize registration errors to NULL and preserve the
static timestamping capabilities.
Fixes: a0d2f20650e8 ("Renesas Ethernet AVB PTP clock driver")
Cc: stable@vger.kernel.org
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: Xuanqiang Luo <redacted>
Link: https://patch.msgid.link/20260811103733.62599-2-xuanqiang.luo@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/renesas/ravb.h | 1 +
drivers/net/ethernet/renesas/ravb_main.c | 3 ++-
drivers/net/ethernet/renesas/ravb_ptp.c | 15 +++++++++++++--
3 files changed, 16 insertions(+), 3 deletions(-)
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h@@ -1034,6 +1034,7 @@ struct ravb_ptp_perout { struct ravb_ptp { struct ptp_clock *clock; struct ptp_clock_info info; + int phc_index; u32 default_addend; u32 current_addend; int extts[N_EXT_TS]; --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1761,7 +1761,7 @@ static int ravb_get_ts_info(struct net_d (1 << HWTSTAMP_FILTER_NONE) | (1 << HWTSTAMP_FILTER_PTP_V2_L2_EVENT) | (1 << HWTSTAMP_FILTER_ALL); - info->phc_index = ptp_clock_index(priv->ptp.clock); + info->phc_index = READ_ONCE(priv->ptp.phc_index); } return 0;
@@ -2953,6 +2953,7 @@ static int ravb_probe(struct platform_de priv->rstc = rstc; priv->ndev = ndev; priv->pdev = pdev; + priv->ptp.phc_index = -1; priv->num_tx_ring[RAVB_BE] = BE_TX_RING_SIZE; priv->num_rx_ring[RAVB_BE] = BE_RX_RING_SIZE; if (info->nc_queues) { --- a/drivers/net/ethernet/renesas/ravb_ptp.c +++ b/drivers/net/ethernet/renesas/ravb_ptp.c
@@ -325,6 +325,7 @@ void ravb_ptp_interrupt(struct net_devic void ravb_ptp_init(struct net_device *ndev, struct platform_device *pdev) { struct ravb_private *priv = netdev_priv(ndev); + struct ptp_clock *clock; unsigned long flags; priv->ptp.info = ravb_ptp_info;
@@ -337,7 +338,15 @@ void ravb_ptp_init(struct net_device *nd ravb_modify(ndev, GCCR, GCCR_TCSS, GCCR_TCSS_ADJGPTP); spin_unlock_irqrestore(&priv->lock, flags); - priv->ptp.clock = ptp_clock_register(&priv->ptp.info, &pdev->dev); + clock = ptp_clock_register(&priv->ptp.info, &pdev->dev); + if (IS_ERR(clock)) { + netdev_err(ndev, "failed to register PTP clock: %pe\n", clock); + clock = NULL; + } + + priv->ptp.clock = clock; + if (clock) + WRITE_ONCE(priv->ptp.phc_index, ptp_clock_index(clock)); } void ravb_ptp_stop(struct net_device *ndev)
@@ -347,5 +356,7 @@ void ravb_ptp_stop(struct net_device *nd ravb_write(ndev, 0, GIC); ravb_write(ndev, 0, GIS); - ptp_clock_unregister(priv->ptp.clock); + WRITE_ONCE(priv->ptp.phc_index, -1); + if (priv->ptp.clock) + ptp_clock_unregister(priv->ptp.clock); }