Commit e1406330d70e for kernel
commit e1406330d70e56dd44fa6fbafc86e77e5c80c122
Author: Runyu Xiao <runyu.xiao@seu.edu.cn>
Date: Tue Sep 8 18:39:24 2026 +0800
net: macb: initialize PTP state before registering clock
gem_ptp_init() registers the PTP clock before initializing
bp->tsu_clk_lock and the TSU hardware. Since ptp_clock_register()
publishes the PTP character device, userspace may invoke PTP callbacks
before the lock and hardware are ready.
In addition, gem_ptp_init() is called from both the interface open and
resume paths. Reinitializing tsu_clk_lock there can reset the lock while
timestamp processing is using it.
This race is theoretical and has not been observed in practice.
Initialize tsu_clk_lock once during probe and initialize the TSU before
registering the PTP clock.
Fixes: ab91f0a9b5f4 ("net: macb: Add hardware PTP support")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/netdev/20260904030439.3994047-1-runyu.xiao@seu.edu.cn/
Reviewed-by: Théo Lebrun <theo.lebrun@bootlin.com>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Link: https://patch.msgid.link/20260908103924.607033-1-runyu.xiao@seu.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 77dec2d6e3fb..4cb5d7088d43 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -5883,6 +5883,7 @@ static int macb_probe(struct platform_device *pdev)
}
spin_lock_init(&bp->lock);
spin_lock_init(&bp->stats_lock);
+ spin_lock_init(&bp->tsu_clk_lock);
/* setup capabilities */
macb_configure_caps(bp, macb_config);
diff --git a/drivers/net/ethernet/cadence/macb_ptp.c b/drivers/net/ethernet/cadence/macb_ptp.c
index e5195d7dac1d..6d9166389988 100644
--- a/drivers/net/ethernet/cadence/macb_ptp.c
+++ b/drivers/net/ethernet/cadence/macb_ptp.c
@@ -334,6 +334,7 @@ void gem_ptp_init(struct net_device *netdev)
bp->tsu_rate = bp->ptp_info->get_tsu_rate(bp);
bp->ptp_clock_info.max_adj = bp->ptp_info->get_ptp_max_adj();
gem_ptp_init_timer(bp);
+ gem_ptp_init_tsu(bp);
bp->ptp_clock = ptp_clock_register(&bp->ptp_clock_info, &netdev->dev);
if (IS_ERR(bp->ptp_clock)) {
pr_err("ptp clock register failed: %ld\n",
@@ -345,10 +346,6 @@ void gem_ptp_init(struct net_device *netdev)
return;
}
- spin_lock_init(&bp->tsu_clk_lock);
-
- gem_ptp_init_tsu(bp);
-
dev_info(&bp->pdev->dev, "%s ptp clock registered.\n",
GEM_PTP_TIMER_NAME);
}