[PATCH] net: pse-pd: pd692x0: reduce stack usage in pd692x0_setup_pi_matrix

[PATCH] net: pse-pd: pd692x0: reduce stack usage in pd692x0_setup_pi_matrix

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

The pd692x0_manager array in this function is really too big to fit on the
stack, though this never triggered a warning until a recent patch made
it slightly bigger:

drivers/net/pse-pd/pd692x0.c: In function 'pd692x0_setup_pi_matrix':
drivers/net/pse-pd/pd692x0.c:1210:1: error: the frame size of 1584 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

Change the function to dynamically allocate the array here.

Fixes: 359754013e6a ("net: pse-pd: pd692x0: Add support for PSE PI priority feature")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/pse-pd/pd692x0.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/pse-pd/pd692x0.c b/drivers/net/pse-pd/pd692x0.c
index 4de004813560..399ce9febda4 100644
--- a/drivers/net/pse-pd/pd692x0.c
+++ b/drivers/net/pse-pd/pd692x0.c
@@ -860,7 +860,7 @@ pd692x0_of_get_ports_manager(struct pd692x0_priv *priv,
 
 static int
 pd692x0_of_get_managers(struct pd692x0_priv *priv,
-			struct pd692x0_manager manager[PD692X0_MAX_MANAGERS])
+			struct pd692x0_manager *manager)
 {
 	struct device_node *managers_node, *node;
 	int ret, nmanagers, i, j;
@@ -1164,7 +1164,7 @@ pd692x0_write_ports_matrix(struct pd692x0_priv *priv,
 
 static int pd692x0_setup_pi_matrix(struct pse_controller_dev *pcdev)
 {
-	struct pd692x0_manager manager[PD692X0_MAX_MANAGERS] = {0};
+	struct pd692x0_manager *manager __free(kfree) = NULL;
 	struct pd692x0_priv *priv = to_pd692x0_priv(pcdev);
 	struct pd692x0_matrix port_matrix[PD692X0_MAX_PIS];
 	int ret, i, j, nmanagers;
@@ -1174,6 +1174,10 @@ static int pd692x0_setup_pi_matrix(struct pse_controller_dev *pcdev)
 	    priv->fw_state != PD692X0_FW_COMPLETE)
 		return 0;
 
+	manager = kcalloc(PD692X0_MAX_MANAGERS, sizeof(*manager), GFP_KERNEL);
+	if (!manager)
+		return -ENOMEM;
+
 	ret = pd692x0_of_get_managers(priv, manager);
 	if (ret < 0)
 		return ret;
-- 
2.39.5

Re: [PATCH] net: pse-pd: pd692x0: reduce stack usage in pd692x0_setup_pi_matrix

[Kory Maincent]

Le Wed,  9 Jul 2025 17:32:04 +0200,
Arnd Bergmann <arnd@kernel.org> a écrit :

> From: Arnd Bergmann <arnd@arndb.de>
> 
> The pd692x0_manager array in this function is really too big to fit on the
> stack, though this never triggered a warning until a recent patch made
> it slightly bigger:
> 
> drivers/net/pse-pd/pd692x0.c: In function 'pd692x0_setup_pi_matrix':
> drivers/net/pse-pd/pd692x0.c:1210:1: error: the frame size of 1584 bytes is
> larger than 1536 bytes [-Werror=frame-larger-than=]
> 
> Change the function to dynamically allocate the array here.

Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>

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

Re: [PATCH] net: pse-pd: pd692x0: reduce stack usage in pd692x0_setup_pi_matrix

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed,  9 Jul 2025 17:32:04 +0200 you wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The pd692x0_manager array in this function is really too big to fit on the
> stack, though this never triggered a warning until a recent patch made
> it slightly bigger:
> 
> drivers/net/pse-pd/pd692x0.c: In function 'pd692x0_setup_pi_matrix':
> drivers/net/pse-pd/pd692x0.c:1210:1: error: the frame size of 1584 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]
> 
> [...]

Here is the summary with links:
  - net: pse-pd: pd692x0: reduce stack usage in pd692x0_setup_pi_matrix
    https://git.kernel.org/netdev/net-next/c/d12b3dc10609

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html