[PATCH net-next v2 3/3] net: reject a netdev that implements only one hwtstamp NDO
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IN NET-NEXT
From: Nicolai Buchwitz <nb@tipi-net.de>
Date: 2026-10-02 09:42:33
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lkml
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Queued in net-next as 810a662abcd5 on 2026-10-06.
ndo_hwtstamp_get and ndo_hwtstamp_set only make sense as a pair. A driver providing just one gets no complaint today, and the mismatch turns up in user space, where a set can succeed while the matching get fails. Catch it at registration instead. Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de> --- net/core/dev.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/net/core/dev.c b/net/core/dev.c
index ca7f4844cc40..db765cb5811e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -11462,6 +11462,11 @@ static int netdev_check_ops(struct net_device *dev) return -EINVAL; } + if (!ops->ndo_hwtstamp_get != !ops->ndo_hwtstamp_set) { + netdev_WARN(dev, "driver implements only one hwtstamp NDO\n"); + return -EINVAL; + } + if (netdev_need_ops_lock(dev) && ops->ndo_set_rx_mode && !ops->ndo_set_rx_mode_async) { netdev_WARN(dev, "ops-locked drivers should use ndo_set_rx_mode_async\n");
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2.53.0