[PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[Joas Antonio dos Santos]

macsec_fs_id_del() removes a struct mlx5_fs_id from its rhashtable with
rhashtable_remove_fast() and then frees it with kfree() right away.

The TX (SCI) table is read locklessly from the transmit path:
mlx5e_macsec_handle_tx_skb() and mlx5e_macsec_tx_build_eseg() call
mlx5_macsec_fs_get_fs_id_from_hashtable(), which does
rhashtable_lookup() under rcu_read_lock() and then reads
mlx5_fs_id->id. A transmit that looked the entry up just before it was
removed reads freed memory.

Before commit d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec
device inside macsec steering") the SCI table held struct
mlx5e_macsec_sa directly, and mlx5e_macsec_del_txsa() freed it with
kfree_rcu_mightsleep(). That commit moved the table into macsec_fs.c
with the new struct mlx5_fs_id, but frees it with a plain kfree().

Add an rcu_head to struct mlx5_fs_id and free it with kfree_rcu().

The same issue was flagged by the Sashiko AI review as a pre-existing
problem while reviewing the HW-GRO for PSP series.

Fixes: d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec device inside macsec steering")
Link: https://lore.kernel.org/all/20260909065542.4B80D1F00ACA@smtp.kernel.org/
Signed-off-by: Joas Antonio dos Santos <joasantonio108@gmail.com>
Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5
---
v2:
- Drop the macsec.c hunk: the sc_xarray_element free was already fixed
  by ad17ad50b8dc ("net: mlx5e: Fix use-after-free of the MACsec xarray
  entry on RX SC deletion"). (Simon)
- Embed an rcu_head and use kfree_rcu() instead of
  kvfree_rcu_mightsleep(). (Simon)
- Fixes: now points at the commit that introduced the kfree().
- v1: https://lore.kernel.org/all/179285888829.90275.17386097105525068016@gmail.com/

Testing: compile-tested only (arm64, W=1, CONFIG_MLX5_MACSEC=y, no new
warnings). I do not have
MACsec-capable ConnectX hardware, so this was not run on a device.

 drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
@@ -94,6 +94,7 @@ struct mlx5_fs_id {
 	refcount_t refcnt;
 	sci_t sci;
 	struct rhash_head hash;
+	struct rcu_head rcu;
 };

 struct mlx5_macsec_device {
@@ -684,7 +685,7 @@ static void macsec_fs_id_del(struct list_head *macsec_devices_list, u32 fs_id,

 	xa_erase(fs_id_xa, fs_id);

-	kfree(fs_id_found);
+	kfree_rcu(fs_id_found, rcu);

 	if (macsec_fs_is_macsec_device_empty(macsec_device)) {
 		list_del(&macsec_device->macsec_devices_list_entry);
--
2.39.5

Re: [PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[Simon Horman]

On Tue, Oct 27, 2026 at 06:17:06PM -0300, Joas Antonio dos Santos wrote:
> macsec_fs_id_del() removes a struct mlx5_fs_id from its rhashtable with
> rhashtable_remove_fast() and then frees it with kfree() right away.
> 
> The TX (SCI) table is read locklessly from the transmit path:
> mlx5e_macsec_handle_tx_skb() and mlx5e_macsec_tx_build_eseg() call
> mlx5_macsec_fs_get_fs_id_from_hashtable(), which does
> rhashtable_lookup() under rcu_read_lock() and then reads
> mlx5_fs_id->id. A transmit that looked the entry up just before it was
> removed reads freed memory.
> 
> Before commit d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec
> device inside macsec steering") the SCI table held struct
> mlx5e_macsec_sa directly, and mlx5e_macsec_del_txsa() freed it with
> kfree_rcu_mightsleep(). That commit moved the table into macsec_fs.c
> with the new struct mlx5_fs_id, but frees it with a plain kfree().
> 
> Add an rcu_head to struct mlx5_fs_id and free it with kfree_rcu().
> 
> The same issue was flagged by the Sashiko AI review as a pre-existing
> problem while reviewing the HW-GRO for PSP series.
> 
> Fixes: d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec device inside macsec steering")
> Link: https://lore.kernel.org/all/20260909065542.4B80D1F00ACA@smtp.kernel.org/
> Signed-off-by: Joas Antonio dos Santos <joasantonio108@gmail.com>
> Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5
> ---
> v2:
> - Drop the macsec.c hunk: the sc_xarray_element free was already fixed
>   by ad17ad50b8dc ("net: mlx5e: Fix use-after-free of the MACsec xarray
>   entry on RX SC deletion"). (Simon)
> - Embed an rcu_head and use kfree_rcu() instead of
>   kvfree_rcu_mightsleep(). (Simon)
> - Fixes: now points at the commit that introduced the kfree().
> - v1: https://lore.kernel.org/all/179285888829.90275.17386097105525068016@gmail.com/
> 
> Testing: compile-tested only (arm64, W=1, CONFIG_MLX5_MACSEC=y, no new
> warnings). I do not have
> MACsec-capable ConnectX hardware, so this was not run on a device.

Thanks for the update, and testing and discovery information.

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[Paolo Abeni]

On 10/27/26 22:17, Joas Antonio dos Santos wrote:
> macsec_fs_id_del() removes a struct mlx5_fs_id from its rhashtable with
> rhashtable_remove_fast() and then frees it with kfree() right away.
> 
> The TX (SCI) table is read locklessly from the transmit path:
> mlx5e_macsec_handle_tx_skb() and mlx5e_macsec_tx_build_eseg() call
> mlx5_macsec_fs_get_fs_id_from_hashtable(), which does
> rhashtable_lookup() under rcu_read_lock() and then reads
> mlx5_fs_id->id. A transmit that looked the entry up just before it was
> removed reads freed memory.
> 
> Before commit d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec
> device inside macsec steering") the SCI table held struct
> mlx5e_macsec_sa directly, and mlx5e_macsec_del_txsa() freed it with
> kfree_rcu_mightsleep(). That commit moved the table into macsec_fs.c
> with the new struct mlx5_fs_id, but frees it with a plain kfree().
> 
> Add an rcu_head to struct mlx5_fs_id and free it with kfree_rcu().
> 
> The same issue was flagged by the Sashiko AI review as a pre-existing
> problem while reviewing the HW-GRO for PSP series.
> 
> Fixes: d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec device inside macsec steering")
> Link: https://lore.kernel.org/all/20260909065542.4B80D1F00ACA@smtp.kernel.org/
> Signed-off-by: Joas Antonio dos Santos <joasantonio108@gmail.com>
> Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5
Waiting for an explicit ack from Mellanox.

/P

Re: [PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[Paolo Abeni]

On 11/2/26 12:39, Paolo Abeni wrote:
> On 10/27/26 22:17, Joas Antonio dos Santos wrote:
>> macsec_fs_id_del() removes a struct mlx5_fs_id from its rhashtable with
>> rhashtable_remove_fast() and then frees it with kfree() right away.
>>
>> The TX (SCI) table is read locklessly from the transmit path:
>> mlx5e_macsec_handle_tx_skb() and mlx5e_macsec_tx_build_eseg() call
>> mlx5_macsec_fs_get_fs_id_from_hashtable(), which does
>> rhashtable_lookup() under rcu_read_lock() and then reads
>> mlx5_fs_id->id. A transmit that looked the entry up just before it was
>> removed reads freed memory.
>>
>> Before commit d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec
>> device inside macsec steering") the SCI table held struct
>> mlx5e_macsec_sa directly, and mlx5e_macsec_del_txsa() freed it with
>> kfree_rcu_mightsleep(). That commit moved the table into macsec_fs.c
>> with the new struct mlx5_fs_id, but frees it with a plain kfree().
>>
>> Add an rcu_head to struct mlx5_fs_id and free it with kfree_rcu().
>>
>> The same issue was flagged by the Sashiko AI review as a pre-existing
>> problem while reviewing the HW-GRO for PSP series.
>>
>> Fixes: d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec device inside macsec steering")
>> Link: https://lore.kernel.org/all/20260909065542.4B80D1F00ACA@smtp.kernel.org/
>> Signed-off-by: Joas Antonio dos Santos <joasantonio108@gmail.com>
>> Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5
> Waiting for an explicit ack from Mellanox.
Actually Dave already applied this one, but the bot did not catch-up.

Sorry for the noise.

/P

Re: [PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[Cosmin Ratiu]

On Tue, 2026-10-27 at 18:17 -0300, Joas Antonio dos Santos wrote:
> macsec_fs_id_del() removes a struct mlx5_fs_id from its rhashtable
> with
> rhashtable_remove_fast() and then frees it with kfree() right away.
> 
> The TX (SCI) table is read locklessly from the transmit path:
> mlx5e_macsec_handle_tx_skb() and mlx5e_macsec_tx_build_eseg() call
> mlx5_macsec_fs_get_fs_id_from_hashtable(), which does
> rhashtable_lookup() under rcu_read_lock() and then reads
> mlx5_fs_id->id. A transmit that looked the entry up just before it
> was
> removed reads freed memory.
> 
> Before commit d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per
> MACsec
> device inside macsec steering") the SCI table held struct
> mlx5e_macsec_sa directly, and mlx5e_macsec_del_txsa() freed it with
> kfree_rcu_mightsleep(). That commit moved the table into macsec_fs.c
> with the new struct mlx5_fs_id, but frees it with a plain kfree().
> 
> Add an rcu_head to struct mlx5_fs_id and free it with kfree_rcu().
> 
> The same issue was flagged by the Sashiko AI review as a pre-existing
> problem while reviewing the HW-GRO for PSP series.
> 
> Fixes: d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec
> device inside macsec steering")
> Link:
> https://lore.kernel.org/all/20260909065542.4B80D1F00ACA@smtp.kernel.org/
> Signed-off-by: Joas Antonio dos Santos <joasantonio108@gmail.com>
> Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5
> ---
> v2:
> - Drop the macsec.c hunk: the sc_xarray_element free was already
> fixed
>   by ad17ad50b8dc ("net: mlx5e: Fix use-after-free of the MACsec
> xarray
>   entry on RX SC deletion"). (Simon)
> - Embed an rcu_head and use kfree_rcu() instead of
>   kvfree_rcu_mightsleep(). (Simon)
> - Fixes: now points at the commit that introduced the kfree().
> - v1:
> https://lore.kernel.org/all/179285888829.90275.17386097105525068016@gmail.com/
> 
> Testing: compile-tested only (arm64, W=1, CONFIG_MLX5_MACSEC=y, no
> new
> warnings). I do not have
> MACsec-capable ConnectX hardware, so this was not run on a device.
> 
>  drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
> b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
> --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
> @@ -94,6 +94,7 @@ struct mlx5_fs_id {
>  	refcount_t refcnt;
>  	sci_t sci;
>  	struct rhash_head hash;
> +	struct rcu_head rcu;
>  };
> 
>  struct mlx5_macsec_device {
> @@ -684,7 +685,7 @@ static void macsec_fs_id_del(struct list_head
> *macsec_devices_list, u32 fs_id,
> 
>  	xa_erase(fs_id_xa, fs_id);
> 
> -	kfree(fs_id_found);
> +	kfree_rcu(fs_id_found, rcu);
> 
>  	if (macsec_fs_is_macsec_device_empty(macsec_device)) {
>  		list_del(&macsec_device->macsec_devices_list_entry);
> --
> 2.39.5

Thank you for the fix, it looks good.

Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>

Re: [PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[Tariq Toukan]

On 04/11/2026 13:20, Cosmin Ratiu wrote:
> On Tue, 2026-10-27 at 18:17 -0300, Joas Antonio dos Santos wrote:
>> macsec_fs_id_del() removes a struct mlx5_fs_id from its rhashtable
>> with
>> rhashtable_remove_fast() and then frees it with kfree() right away.
>>
>> The TX (SCI) table is read locklessly from the transmit path:
>> mlx5e_macsec_handle_tx_skb() and mlx5e_macsec_tx_build_eseg() call
>> mlx5_macsec_fs_get_fs_id_from_hashtable(), which does
>> rhashtable_lookup() under rcu_read_lock() and then reads
>> mlx5_fs_id->id. A transmit that looked the entry up just before it
>> was
>> removed reads freed memory.
>>
>> Before commit d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per
>> MACsec
>> device inside macsec steering") the SCI table held struct
>> mlx5e_macsec_sa directly, and mlx5e_macsec_del_txsa() freed it with
>> kfree_rcu_mightsleep(). That commit moved the table into macsec_fs.c
>> with the new struct mlx5_fs_id, but frees it with a plain kfree().
>>
>> Add an rcu_head to struct mlx5_fs_id and free it with kfree_rcu().
>>
>> The same issue was flagged by the Sashiko AI review as a pre-existing
>> problem while reviewing the HW-GRO for PSP series.
>>
>> Fixes: d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec
>> device inside macsec steering")
>> Link:
>> https://lore.kernel.org/all/20260909065542.4B80D1F00ACA@smtp.kernel.org/
>> Signed-off-by: Joas Antonio dos Santos <joasantonio108@gmail.com>
>> Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5
>> ---
>> v2:
>> - Drop the macsec.c hunk: the sc_xarray_element free was already
>> fixed
>>    by ad17ad50b8dc ("net: mlx5e: Fix use-after-free of the MACsec
>> xarray
>>    entry on RX SC deletion"). (Simon)
>> - Embed an rcu_head and use kfree_rcu() instead of
>>    kvfree_rcu_mightsleep(). (Simon)
>> - Fixes: now points at the commit that introduced the kfree().
>> - v1:
>> https://lore.kernel.org/all/179285888829.90275.17386097105525068016@gmail.com/
>>
>> Testing: compile-tested only (arm64, W=1, CONFIG_MLX5_MACSEC=y, no
>> new
>> warnings). I do not have
>> MACsec-capable ConnectX hardware, so this was not run on a device.
>>
>>   drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>> b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>> @@ -94,6 +94,7 @@ struct mlx5_fs_id {
>>   	refcount_t refcnt;
>>   	sci_t sci;
>>   	struct rhash_head hash;
>> +	struct rcu_head rcu;
>>   };
>>
>>   struct mlx5_macsec_device {
>> @@ -684,7 +685,7 @@ static void macsec_fs_id_del(struct list_head
>> *macsec_devices_list, u32 fs_id,
>>
>>   	xa_erase(fs_id_xa, fs_id);
>>
>> -	kfree(fs_id_found);
>> +	kfree_rcu(fs_id_found, rcu);
>>
>>   	if (macsec_fs_is_macsec_device_empty(macsec_device)) {
>>   		list_del(&macsec_device->macsec_devices_list_entry);
>> --
>> 2.39.5
> 
> Thank you for the fix, it looks good.
> 
> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>

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

Re: [PATCH net v2] net/mlx5: macsec: free struct mlx5_fs_id after an RCU grace period

[Paolo Abeni]

On 11/4/26 13:49, Tariq Toukan wrote:
> On 04/11/2026 13:20, Cosmin Ratiu wrote:
>> On Tue, 2026-10-27 at 18:17 -0300, Joas Antonio dos Santos wrote:
>>> macsec_fs_id_del() removes a struct mlx5_fs_id from its rhashtable
>>> with
>>> rhashtable_remove_fast() and then frees it with kfree() right away.
>>>
>>> The TX (SCI) table is read locklessly from the transmit path:
>>> mlx5e_macsec_handle_tx_skb() and mlx5e_macsec_tx_build_eseg() call
>>> mlx5_macsec_fs_get_fs_id_from_hashtable(), which does
>>> rhashtable_lookup() under rcu_read_lock() and then reads
>>> mlx5_fs_id->id. A transmit that looked the entry up just before it
>>> was
>>> removed reads freed memory.
>>>
>>> Before commit d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per
>>> MACsec
>>> device inside macsec steering") the SCI table held struct
>>> mlx5e_macsec_sa directly, and mlx5e_macsec_del_txsa() freed it with
>>> kfree_rcu_mightsleep(). That commit moved the table into macsec_fs.c
>>> with the new struct mlx5_fs_id, but frees it with a plain kfree().
>>>
>>> Add an rcu_head to struct mlx5_fs_id and free it with kfree_rcu().
>>>
>>> The same issue was flagged by the Sashiko AI review as a pre-existing
>>> problem while reviewing the HW-GRO for PSP series.
>>>
>>> Fixes: d4ece08f4b1d ("net/mlx5: Maintain fs_id xarray per MACsec
>>> device inside macsec steering")
>>> Link:
>>> https://lore.kernel.org/all/20260909065542.4B80D1F00ACA@smtp.kernel.org/
>>> Signed-off-by: Joas Antonio dos Santos <joasantonio108@gmail.com>
>>> Assisted-by: Yaga Agent HackerSec Claude:claude-opus-5-5
>>> ---
>>> v2:
>>> - Drop the macsec.c hunk: the sc_xarray_element free was already
>>> fixed
>>>    by ad17ad50b8dc ("net: mlx5e: Fix use-after-free of the MACsec
>>> xarray
>>>    entry on RX SC deletion"). (Simon)
>>> - Embed an rcu_head and use kfree_rcu() instead of
>>>    kvfree_rcu_mightsleep(). (Simon)
>>> - Fixes: now points at the commit that introduced the kfree().
>>> - v1:
>>> https://lore.kernel.org/all/179285888829.90275.17386097105525068016@gmail.com/
>>>
>>> Testing: compile-tested only (arm64, W=1, CONFIG_MLX5_MACSEC=y, no
>>> new
>>> warnings). I do not have
>>> MACsec-capable ConnectX hardware, so this was not run on a device.
>>>
>>>   drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>>> b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>>> --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/macsec_fs.c
>>> @@ -94,6 +94,7 @@ struct mlx5_fs_id {
>>>       refcount_t refcnt;
>>>       sci_t sci;
>>>       struct rhash_head hash;
>>> +    struct rcu_head rcu;
>>>   };
>>>
>>>   struct mlx5_macsec_device {
>>> @@ -684,7 +685,7 @@ static void macsec_fs_id_del(struct list_head
>>> *macsec_devices_list, u32 fs_id,
>>>
>>>       xa_erase(fs_id_xa, fs_id);
>>>
>>> -    kfree(fs_id_found);
>>> +    kfree_rcu(fs_id_found, rcu);
>>>
>>>       if (macsec_fs_is_macsec_device_empty(macsec_device)) {
>>>           list_del(&macsec_device->macsec_devices_list_entry);
>>> -- 
>>> 2.39.5
>>
>> Thank you for the fix, it looks good.
>>
>> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
> 
> Acked-by: Tariq Toukan <tariqt@nvidia.com>

While I have your attention, there is another mlx patch pending:

https://lore.kernel.org/all/20261028145805.54595-3-fourier.thomas@gmail.com/

/P