linux-kernel - Re: [PATCH net] iavf: fix PTP use-after-free during reset

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Message-ID: <9a6a7736-6fdb-468c-9576-6c2db97777d8@intel.com>
Date: Thu, 29 Jan 2026 09:25:35 -0800
From: Jacob Keller <jacob.e.keller@...el.com>
To: Petr Oros <poros@...hat.com>, <netdev@...r.kernel.org>
CC: <ivecera@...hat.com>, <mschmidt@...hat.com>, Tony Nguyen
	<anthony.l.nguyen@...el.com>, Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, "Paolo
 Abeni" <pabeni@...hat.com>, Richard Cochran <richardcochran@...il.com>,
	"Simon Horman" <horms@...nel.org>, Mateusz Polchlopek
	<mateusz.polchlopek@...el.com>, <intel-wired-lan@...ts.osuosl.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net] iavf: fix PTP use-after-free during reset



On 1/29/2026 1:57 AM, Petr Oros wrote:
> Commit 7c01dbfc8a1c5f ("iavf: periodically cache PHC time") introduced a
> worker to cache PHC time, but failed to stop it during reset or disable.
> 
> This creates a race condition where `iavf_reset_task()` or
> `iavf_disable_vf()` free adapter resources (AQ) while the worker is still
> running. If the worker triggers `iavf_queue_ptp_cmd()` during teardown, it
> accesses freed memory/locks, leading to a crash.
> 
> Fix this by calling `iavf_ptp_release()` before tearing down the adapter.
> This ensures `ptp_clock_unregister()` synchronously cancels the worker and
> cleans up the chardev before the backing resources are destroyed.
> 
> Fixes: 7c01dbfc8a1c5f ("iavf: periodically cache PHC time")
> Signed-off-by: Petr Oros <poros@...hat.com>
> ---
>   drivers/net/ethernet/intel/iavf/iavf_main.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
> index 4b0fc8f354bc90..0dd58ce5a53ab1 100644
> --- a/drivers/net/ethernet/intel/iavf/iavf_main.c
> +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
> @@ -3025,6 +3025,8 @@ static void iavf_disable_vf(struct iavf_adapter *adapter)
>   
>   	adapter->flags |= IAVF_FLAG_PF_COMMS_FAILED;
>   
> +	iavf_ptp_release(adapter);
> +
>   	/* We don't use netif_running() because it may be true prior to
>   	 * ndo_open() returning, so we can't assume it means all our open
>   	 * tasks have finished, since we're not holding the rtnl_lock here.
> @@ -3200,6 +3202,8 @@ static void iavf_reset_task(struct work_struct *work)
>   	iavf_change_state(adapter, __IAVF_RESETTING);
>   	adapter->flags &= ~IAVF_FLAG_RESET_PENDING;
>   
> +	iavf_ptp_release(adapter);
> +
>   	/* free the Tx/Rx rings and descriptors, might be better to just
>   	 * re-use them sometime in the future
>   	 */

Thanks for the fix!

Acked-by: Jacob Keller <jacob.e.keller@...el.com>