[PATCH net-next 7/7] net/mlx5: Don't use %pK through tracepoints

Thomas Weißschuh posted 7 patches 10 months ago
There is a newer version of this series
[PATCH net-next 7/7] net/mlx5: Don't use %pK through tracepoints
Posted by Thomas Weißschuh 10 months ago
In the past %pK was preferable to %p as it would not leak raw pointer
values into the kernel log.
Since commit ad67b74d2469 ("printk: hash addresses printed with %p")
the regular %p has been improved to avoid this issue.
Furthermore, restricted pointers ("%pK") were never meant to be used
through tracepoints. They can still unintentionally leak raw pointers or
acquire sleeping looks in atomic contexts.

Switch to the regular pointer formatting which is safer and
easier to reason about.
There are still a few users of %pK left, but these use it through seq_file,
for which its usage is safe.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h
index 0537de86f9817dc80bd897688c539135b1ad37ac..9b0f44253f332aa602a84a1f6d7532a500dd4f55 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h
@@ -28,7 +28,7 @@ DECLARE_EVENT_CLASS(mlx5_sf_dev_template,
 				   __entry->hw_fn_id = sfdev->fn_id;
 				   __entry->sfnum = sfdev->sfnum;
 		    ),
-		    TP_printk("(%s) sfdev=%pK aux_id=%d hw_id=0x%x sfnum=%u\n",
+		    TP_printk("(%s) sfdev=%p aux_id=%d hw_id=0x%x sfnum=%u\n",
 			      __get_str(devname), __entry->sfdev,
 			      __entry->aux_id, __entry->hw_fn_id,
 			      __entry->sfnum)

-- 
2.49.0

RE: [Intel-wired-lan] [PATCH net-next 7/7] net/mlx5: Don't use %pK through tracepoints
Posted by Loktionov, Aleksandr 10 months ago

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Thomas Weißschuh
> Sent: Monday, April 14, 2025 10:26 AM
> To: Jeff Johnson <jjohnson@kernel.org>; Loic Poulain
> <loic.poulain@linaro.org>; Brian Norris <briannorris@chromium.org>;
> Francesco Dolcini <francesco@dolcini.it>; Nguyen, Anthony L
> <anthony.l.nguyen@intel.com>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@intel.com>; Andrew Lunn <andrew+netdev@lunn.ch>;
> David S. Miller <davem@davemloft.net>; Dumazet, Eric
> <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni
> <pabeni@redhat.com>; Saeed Mahameed <saeedm@nvidia.com>; Leon
> Romanovsky <leon@kernel.org>; Tariq Toukan <tariqt@nvidia.com>
> Cc: ath10k@lists.infradead.org; linux-kernel@vger.kernel.org;
> ath11k@lists.infradead.org; ath12k@lists.infradead.org;
> wcn36xx@lists.infradead.org; linux-wireless@vger.kernel.org; intel-wired-
> lan@lists.osuosl.org; netdev@vger.kernel.org; linux-rdma@vger.kernel.org;
> Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> Subject: [Intel-wired-lan] [PATCH net-next 7/7] net/mlx5: Don't use %pK
> through tracepoints
> 
> In the past %pK was preferable to %p as it would not leak raw pointer values
> into the kernel log.
> Since commit ad67b74d2469 ("printk: hash addresses printed with %p") the
> regular %p has been improved to avoid this issue.
> Furthermore, restricted pointers ("%pK") were never meant to be used
> through tracepoints. They can still unintentionally leak raw pointers or acquire
> sleeping looks in atomic contexts.
> 
> Switch to the regular pointer formatting which is safer and easier to reason
> about.
> There are still a few users of %pK left, but these use it through seq_file, for
> which its usage is safe.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h | 2
> +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git
> a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h
> b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h
> index
> 0537de86f9817dc80bd897688c539135b1ad37ac..9b0f44253f332aa602a8
> 4a1f6d7532a500dd4f55 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint
> +++ .h
> @@ -28,7 +28,7 @@ DECLARE_EVENT_CLASS(mlx5_sf_dev_template,
>  				   __entry->hw_fn_id = sfdev->fn_id;
>  				   __entry->sfnum = sfdev->sfnum;
>  		    ),
> -		    TP_printk("(%s) sfdev=%pK aux_id=%d hw_id=0x%x
> sfnum=%u\n",
> +		    TP_printk("(%s) sfdev=%p aux_id=%d hw_id=0x%x
> sfnum=%u\n",
>  			      __get_str(devname), __entry->sfdev,
>  			      __entry->aux_id, __entry->hw_fn_id,
>  			      __entry->sfnum)
> 
> --
> 2.49.0

Re: [PATCH net-next 7/7] net/mlx5: Don't use %pK through tracepoints
Posted by Tariq Toukan 10 months ago

On 14/04/2025 11:26, Thomas Weißschuh wrote:
> In the past %pK was preferable to %p as it would not leak raw pointer
> values into the kernel log.
> Since commit ad67b74d2469 ("printk: hash addresses printed with %p")
> the regular %p has been improved to avoid this issue.
> Furthermore, restricted pointers ("%pK") were never meant to be used
> through tracepoints. They can still unintentionally leak raw pointers or
> acquire sleeping looks in atomic contexts.
> 
> Switch to the regular pointer formatting which is safer and
> easier to reason about.
> There are still a few users of %pK left, but these use it through seq_file,
> for which its usage is safe.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
> ---
>   drivers/net/ethernet/mellanox/mlx5/core/sf/dev/diag/dev_tracepoint.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>