Re: [PATCH net] net: dev_ioctl: take ops lock in hwtstamp lower paths

[Kory Maincent <kory.maincent@bootlin.com>]

On Thu, 4 Sep 2025 21:28:06 +0300
Carolina Jubran <cjubran@nvidia.com> wrote:

> ndo hwtstamp callbacks are expected to run under the per-device ops
> lock. Make the lower get/set paths consistent with the rest of ndo
> invocations.
> 
> Kernel log:
> WARNING: CPU: 13 PID: 51364 at ./include/net/netdev_lock.h:70
> __netdev_update_features+0x4bd/0xe60 ...
> RIP: 0010:__netdev_update_features+0x4bd/0xe60
> ...
> Call Trace:
> <TASK>
> netdev_update_features+0x1f/0x60
> mlx5_hwtstamp_set+0x181/0x290 [mlx5_core]
> mlx5e_hwtstamp_set+0x19/0x30 [mlx5_core]

Where does these two functions come from? They are not mainline.
Else LGTM.

> dev_set_hwtstamp_phylib+0x9f/0x220
> dev_set_hwtstamp_phylib+0x9f/0x220
> dev_set_hwtstamp+0x13d/0x240
> dev_ioctl+0x12f/0x4b0
> sock_ioctl+0x171/0x370
> __x64_sys_ioctl+0x3f7/0x900
> ? __sys_setsockopt+0x69/0xb0
> do_syscall_64+0x6f/0x2e0
> entry_SYSCALL_64_after_hwframe+0x4b/0x53
> ...
> </TASK>
> ....
> ---[ end trace 0000000000000000 ]---
> 
> Fixes: ffb7ed19ac0a ("net: hold netdev instance lock during ioctl operations")
> Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
> Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
> 
> ---
>  net/core/dev_ioctl.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
> index 9c0ad7f4b5d8..ad54b12d4b4c 100644
> --- a/net/core/dev_ioctl.c
> +++ b/net/core/dev_ioctl.c
> @@ -464,8 +464,15 @@ int generic_hwtstamp_get_lower(struct net_device *dev,
>  	if (!netif_device_present(dev))
>  		return -ENODEV;
>  
> -	if (ops->ndo_hwtstamp_get)
> -		return dev_get_hwtstamp_phylib(dev, kernel_cfg);
> +	if (ops->ndo_hwtstamp_get) {
> +		int err;
> +
> +		netdev_lock_ops(dev);
> +		err = dev_get_hwtstamp_phylib(dev, kernel_cfg);
> +		netdev_unlock_ops(dev);
> +
> +		return err;
> +	}
>  
>  	/* Legacy path: unconverted lower driver */
>  	return generic_hwtstamp_ioctl_lower(dev, SIOCGHWTSTAMP, kernel_cfg);
> @@ -481,8 +488,15 @@ int generic_hwtstamp_set_lower(struct net_device *dev,
>  	if (!netif_device_present(dev))
>  		return -ENODEV;
>  
> -	if (ops->ndo_hwtstamp_set)
> -		return dev_set_hwtstamp_phylib(dev, kernel_cfg, extack);
> +	if (ops->ndo_hwtstamp_set) {
> +		int err;
> +
> +		netdev_lock_ops(dev);
> +		err = dev_set_hwtstamp_phylib(dev, kernel_cfg, extack);
> +		netdev_unlock_ops(dev);
> +
> +		return err;
> +	}
>  
>  	/* Legacy path: unconverted lower driver */
>  	return generic_hwtstamp_ioctl_lower(dev, SIOCSHWTSTAMP, kernel_cfg);



-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com