Commit 28b22528 authored Mar 09, 2026 by Jakub Kicinski

page_pool: store detach_time as ktime_t to avoid false-negatives



While testing other changes in vng I noticed that
nl_netdev.page_pool_check flakes. This never happens in real CI.

Turns out vng may boot and get to that test in less than a second.
page_pool_detached() records the detach time in seconds, so if
vng is fast enough detach time is set to 0. Other code treats
0 as "not detached". detach_time is only used to report the state
to the user, so it's not a huge deal in practice but let's fix it.
Store the raw ktime_t (nanoseconds) instead. A nanosecond value
of 0 is practically impossible.

Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Fixes: 69cb4952 ("net: page_pool: report when page pool was destroyed")
Link: https://patch.msgid.link/20260310003907.3540019-1-kuba@kernel.org


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 881a0263

include/net/page_pool/types.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -247,7 +247,7 @@ struct page_pool {
		/* User-facing fields, protected by page_pools_lock */
		struct {
		struct hlist_node list;
		u64 detach_time;
		ktime_t detach_time;
		u32 id;
		} user;
		};

net/core/page_pool_user.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -245,7 +245,7 @@ page_pool_nl_fill(struct sk_buff rsp, const struct page_pool pool,
		goto err_cancel;
		if (pool->user.detach_time &&
		nla_put_uint(rsp, NETDEV_A_PAGE_POOL_DETACH_TIME,
		pool->user.detach_time))
		ktime_divns(pool->user.detach_time, NSEC_PER_SEC)))
		goto err_cancel;

		if (pool->mp_ops && pool->mp_ops->nl_fill(pool->mp_priv, rsp, NULL))
		@@ -337,7 +337,7 @@ int page_pool_list(struct page_pool *pool)
		void page_pool_detached(struct page_pool *pool)
		{
		mutex_lock(&page_pools_lock);
		pool->user.detach_time = ktime_get_boottime_seconds();
		pool->user.detach_time = ktime_get_boottime();
		netdev_nl_page_pool_event(pool, NETDEV_CMD_PAGE_POOL_CHANGE_NTF);
		mutex_unlock(&page_pools_lock);
		}