[PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[Jakub Kicinski]

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.

Fixes: 69cb4952b6f6 ("net: page_pool: report when page pool was destroyed")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: hawk@kernel.org
CC: ilias.apalodimas@linaro.org
---
 include/net/page_pool/types.h | 2 +-
 net/core/page_pool_user.c     | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 0d453484a585..cdd95477af7a 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -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;
 };
diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
index c82a95beceff..fb4ca27358cd 100644
--- a/net/core/page_pool_user.c
+++ b/net/core/page_pool_user.c
@@ -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_to_seconds(pool->user.detach_time)))
 		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);
 }
-- 
2.53.0

Re: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[Eric Dumazet]

On Sat, Mar 7, 2026 at 9:40 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> 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.
>
> Fixes: 69cb4952b6f6 ("net: page_pool: report when page pool was destroyed")
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: hawk@kernel.org
> CC: ilias.apalodimas@linaro.org
> ---
>  include/net/page_pool/types.h | 2 +-
>  net/core/page_pool_user.c     | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
> index 0d453484a585..cdd95477af7a 100644
> --- a/include/net/page_pool/types.h
> +++ b/include/net/page_pool/types.h
> @@ -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;
>  };
> diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
> index c82a95beceff..fb4ca27358cd 100644
> --- a/net/core/page_pool_user.c
> +++ b/net/core/page_pool_user.c
> @@ -245,7 +245,7 @@ page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
>                 goto err_cancel;

It is a bit unclear if we always hold page_pools_lock at this point.

If not, a READ_ONCE(pool->user.detach_time) here would be needed,
and a corresponding WRITE_ONCE() in  page_pool_detached()

>         if (pool->user.detach_time &&
>             nla_put_uint(rsp, NETDEV_A_PAGE_POOL_DETACH_TIME,
> -                        pool->user.detach_time))
> +                        ktime_to_seconds(pool->user.detach_time)))
>                 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);
>  }
> --
> 2.53.0
>

Re: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[kernel test robot]

Hi Jakub,

kernel test robot noticed the following build errors:

[auto build test ERROR on net/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Jakub-Kicinski/page_pool-store-detach_time-as-ktime_t-to-avoid-false-negatives/20260308-044057
base:   net/main
patch link:    https://lore.kernel.org/r/20260307204022.1897614-1-kuba%40kernel.org
patch subject: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives
config: mips-decstation_defconfig (https://download.01.org/0day-ci/archive/20260308/202603081213.0a8noL8L-lkp@intel.com/config)
compiler: mips-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260308/202603081213.0a8noL8L-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603081213.0a8noL8L-lkp@intel.com/

All errors (new ones prefixed by >>):

   net/core/page_pool_user.c: In function 'page_pool_nl_fill':
>> net/core/page_pool_user.c:248:26: error: implicit declaration of function 'ktime_to_seconds'; did you mean 'ktime_get_seconds'? [-Wimplicit-function-declaration]
     248 |                          ktime_to_seconds(pool->user.detach_time)))
         |                          ^~~~~~~~~~~~~~~~
         |                          ktime_get_seconds


vim +248 net/core/page_pool_user.c

   214	
   215	static int
   216	page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
   217			  const struct genl_info *info)
   218	{
   219		size_t inflight, refsz;
   220		unsigned int napi_id;
   221		void *hdr;
   222	
   223		hdr = genlmsg_iput(rsp, info);
   224		if (!hdr)
   225			return -EMSGSIZE;
   226	
   227		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_ID, pool->user.id))
   228			goto err_cancel;
   229	
   230		if (pool->slow.netdev->ifindex != LOOPBACK_IFINDEX &&
   231		    nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX,
   232				pool->slow.netdev->ifindex))
   233			goto err_cancel;
   234	
   235		napi_id = pool->p.napi ? READ_ONCE(pool->p.napi->napi_id) : 0;
   236		if (napi_id_valid(napi_id) &&
   237		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_NAPI_ID, napi_id))
   238			goto err_cancel;
   239	
   240		inflight = page_pool_inflight(pool, false);
   241		refsz =	PAGE_SIZE << pool->p.order;
   242		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT, inflight) ||
   243		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT_MEM,
   244				 inflight * refsz))
   245			goto err_cancel;
   246		if (pool->user.detach_time &&
   247		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_DETACH_TIME,
 > 248				 ktime_to_seconds(pool->user.detach_time)))
   249			goto err_cancel;
   250	
   251		if (pool->mp_ops && pool->mp_ops->nl_fill(pool->mp_priv, rsp, NULL))
   252			goto err_cancel;
   253	
   254		genlmsg_end(rsp, hdr);
   255	
   256		return 0;
   257	err_cancel:
   258		genlmsg_cancel(rsp, hdr);
   259		return -EMSGSIZE;
   260	}
   261	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[kernel test robot]

Hi Jakub,

kernel test robot noticed the following build errors:

[auto build test ERROR on net/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Jakub-Kicinski/page_pool-store-detach_time-as-ktime_t-to-avoid-false-negatives/20260308-044057
base:   net/main
patch link:    https://lore.kernel.org/r/20260307204022.1897614-1-kuba%40kernel.org
patch subject: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives
config: loongarch-randconfig-001-20260308 (https://download.01.org/0day-ci/archive/20260308/202603081213.mN3LtMM5-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260308/202603081213.mN3LtMM5-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603081213.mN3LtMM5-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/core/page_pool_user.c:248:5: error: call to undeclared function 'ktime_to_seconds'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     248 |                          ktime_to_seconds(pool->user.detach_time)))
         |                          ^
   net/core/page_pool_user.c:248:5: note: did you mean 'ktime_get_seconds'?
   include/linux/timekeeping.h:59:17: note: 'ktime_get_seconds' declared here
      59 | extern time64_t ktime_get_seconds(void);
         |                 ^
   1 error generated.


vim +/ktime_to_seconds +248 net/core/page_pool_user.c

   214	
   215	static int
   216	page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
   217			  const struct genl_info *info)
   218	{
   219		size_t inflight, refsz;
   220		unsigned int napi_id;
   221		void *hdr;
   222	
   223		hdr = genlmsg_iput(rsp, info);
   224		if (!hdr)
   225			return -EMSGSIZE;
   226	
   227		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_ID, pool->user.id))
   228			goto err_cancel;
   229	
   230		if (pool->slow.netdev->ifindex != LOOPBACK_IFINDEX &&
   231		    nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX,
   232				pool->slow.netdev->ifindex))
   233			goto err_cancel;
   234	
   235		napi_id = pool->p.napi ? READ_ONCE(pool->p.napi->napi_id) : 0;
   236		if (napi_id_valid(napi_id) &&
   237		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_NAPI_ID, napi_id))
   238			goto err_cancel;
   239	
   240		inflight = page_pool_inflight(pool, false);
   241		refsz =	PAGE_SIZE << pool->p.order;
   242		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT, inflight) ||
   243		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT_MEM,
   244				 inflight * refsz))
   245			goto err_cancel;
   246		if (pool->user.detach_time &&
   247		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_DETACH_TIME,
 > 248				 ktime_to_seconds(pool->user.detach_time)))
   249			goto err_cancel;
   250	
   251		if (pool->mp_ops && pool->mp_ops->nl_fill(pool->mp_priv, rsp, NULL))
   252			goto err_cancel;
   253	
   254		genlmsg_end(rsp, hdr);
   255	
   256		return 0;
   257	err_cancel:
   258		genlmsg_cancel(rsp, hdr);
   259		return -EMSGSIZE;
   260	}
   261	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[kernel test robot]

Hi Jakub,

kernel test robot noticed the following build errors:

[auto build test ERROR on net/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Jakub-Kicinski/page_pool-store-detach_time-as-ktime_t-to-avoid-false-negatives/20260308-044057
base:   net/main
patch link:    https://lore.kernel.org/r/20260307204022.1897614-1-kuba%40kernel.org
patch subject: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20260308/202603080650.SZhWEYVL-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260308/202603080650.SZhWEYVL-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603080650.SZhWEYVL-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/core/page_pool_user.c:248:5: error: call to undeclared function 'ktime_to_seconds'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     248 |                          ktime_to_seconds(pool->user.detach_time)))
         |                          ^
   net/core/page_pool_user.c:248:5: note: did you mean 'ktime_get_seconds'?
   include/linux/timekeeping.h:59:17: note: 'ktime_get_seconds' declared here
      59 | extern time64_t ktime_get_seconds(void);
         |                 ^
   1 error generated.


vim +/ktime_to_seconds +248 net/core/page_pool_user.c

   214	
   215	static int
   216	page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
   217			  const struct genl_info *info)
   218	{
   219		size_t inflight, refsz;
   220		unsigned int napi_id;
   221		void *hdr;
   222	
   223		hdr = genlmsg_iput(rsp, info);
   224		if (!hdr)
   225			return -EMSGSIZE;
   226	
   227		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_ID, pool->user.id))
   228			goto err_cancel;
   229	
   230		if (pool->slow.netdev->ifindex != LOOPBACK_IFINDEX &&
   231		    nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX,
   232				pool->slow.netdev->ifindex))
   233			goto err_cancel;
   234	
   235		napi_id = pool->p.napi ? READ_ONCE(pool->p.napi->napi_id) : 0;
   236		if (napi_id_valid(napi_id) &&
   237		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_NAPI_ID, napi_id))
   238			goto err_cancel;
   239	
   240		inflight = page_pool_inflight(pool, false);
   241		refsz =	PAGE_SIZE << pool->p.order;
   242		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT, inflight) ||
   243		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT_MEM,
   244				 inflight * refsz))
   245			goto err_cancel;
   246		if (pool->user.detach_time &&
   247		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_DETACH_TIME,
 > 248				 ktime_to_seconds(pool->user.detach_time)))
   249			goto err_cancel;
   250	
   251		if (pool->mp_ops && pool->mp_ops->nl_fill(pool->mp_priv, rsp, NULL))
   252			goto err_cancel;
   253	
   254		genlmsg_end(rsp, hdr);
   255	
   256		return 0;
   257	err_cancel:
   258		genlmsg_cancel(rsp, hdr);
   259		return -EMSGSIZE;
   260	}
   261	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[kernel test robot]

Hi Jakub,

kernel test robot noticed the following build errors:

[auto build test ERROR on net/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Jakub-Kicinski/page_pool-store-detach_time-as-ktime_t-to-avoid-false-negatives/20260308-044057
base:   net/main
patch link:    https://lore.kernel.org/r/20260307204022.1897614-1-kuba%40kernel.org
patch subject: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20260308/202603080604.nGijPf4B-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260308/202603080604.nGijPf4B-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603080604.nGijPf4B-lkp@intel.com/

All errors (new ones prefixed by >>):

   net/core/page_pool_user.c: In function 'page_pool_nl_fill':
>> net/core/page_pool_user.c:248:26: error: implicit declaration of function 'ktime_to_seconds'; did you mean 'ktime_get_seconds'? [-Wimplicit-function-declaration]
     248 |                          ktime_to_seconds(pool->user.detach_time)))
         |                          ^~~~~~~~~~~~~~~~
         |                          ktime_get_seconds


vim +248 net/core/page_pool_user.c

   214	
   215	static int
   216	page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
   217			  const struct genl_info *info)
   218	{
   219		size_t inflight, refsz;
   220		unsigned int napi_id;
   221		void *hdr;
   222	
   223		hdr = genlmsg_iput(rsp, info);
   224		if (!hdr)
   225			return -EMSGSIZE;
   226	
   227		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_ID, pool->user.id))
   228			goto err_cancel;
   229	
   230		if (pool->slow.netdev->ifindex != LOOPBACK_IFINDEX &&
   231		    nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX,
   232				pool->slow.netdev->ifindex))
   233			goto err_cancel;
   234	
   235		napi_id = pool->p.napi ? READ_ONCE(pool->p.napi->napi_id) : 0;
   236		if (napi_id_valid(napi_id) &&
   237		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_NAPI_ID, napi_id))
   238			goto err_cancel;
   239	
   240		inflight = page_pool_inflight(pool, false);
   241		refsz =	PAGE_SIZE << pool->p.order;
   242		if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT, inflight) ||
   243		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_INFLIGHT_MEM,
   244				 inflight * refsz))
   245			goto err_cancel;
   246		if (pool->user.detach_time &&
   247		    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_DETACH_TIME,
 > 248				 ktime_to_seconds(pool->user.detach_time)))
   249			goto err_cancel;
   250	
   251		if (pool->mp_ops && pool->mp_ops->nl_fill(pool->mp_priv, rsp, NULL))
   252			goto err_cancel;
   253	
   254		genlmsg_end(rsp, hdr);
   255	
   256		return 0;
   257	err_cancel:
   258		genlmsg_cancel(rsp, hdr);
   259		return -EMSGSIZE;
   260	}
   261	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[Jakub Kicinski]

On Sun, 8 Mar 2026 01:10:55 +0100 Eric Dumazet wrote:
> > --- a/net/core/page_pool_user.c
> > +++ b/net/core/page_pool_user.c
> > @@ -245,7 +245,7 @@ page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
> >                 goto err_cancel;  
> 
> It is a bit unclear if we always hold page_pools_lock at this point.
> 
> If not, a READ_ONCE(pool->user.detach_time) here would be needed,
> and a corresponding WRITE_ONCE() in  page_pool_detached()

There's a bit of convoluted wrapping to share the code between page
pool access and access to stats, but AFAICT page_pools_lock should 
be consistently held by readers and writers.

Re: [PATCH net] page_pool: store detach_time as ktime_t to avoid false-negatives

[Jesper Dangaard Brouer]

On 07/03/2026 21.40, Jakub Kicinski wrote:
> 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.
> 
> Fixes: 69cb4952b6f6 ("net: page_pool: report when page pool was destroyed")
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: hawk@kernel.org

LGTM -- after addressing in build errors... likely a missing include?

Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>


> CC: ilias.apalodimas@linaro.org
> ---
>   include/net/page_pool/types.h | 2 +-
>   net/core/page_pool_user.c     | 4 ++--
>   2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
> index 0d453484a585..cdd95477af7a 100644
> --- a/include/net/page_pool/types.h
> +++ b/include/net/page_pool/types.h
> @@ -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;
>   };
> diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
> index c82a95beceff..fb4ca27358cd 100644
> --- a/net/core/page_pool_user.c
> +++ b/net/core/page_pool_user.c
> @@ -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_to_seconds(pool->user.detach_time)))

Hmm.. is this ktime_to_seconds even defined?

A quick look tells me that we could use:

  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);
>   }