[PATCH net] net/mlx5: Only set num_doorbells on a fully initialized SF

[PATCH net] net/mlx5: Only set num_doorbells on a fully initialized SF

[Tariq Toukan]

From: Cosmin Ratiu <cratiu@nvidia.com>

The validation for the num_doorbells devlink param rejects values
greater than num_channels. For lightweight SFs, this ends up accessing
a NULL priv->eq_table, leading to a crash.

Fix that by rejecting setting num_doorbells on uninitialized SFs.

Fixes: 11bbcfb7668c ("net/mlx5e: Use the 'num_doorbells' devlink param")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/devlink.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
index b9026cc64383..30a97e48dda7 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
@@ -542,6 +542,12 @@ static int mlx5_devlink_num_doorbells_validate(struct devlink *devlink, u32 id,
 	u32 val32 = val->vu32;
 	u32 max_num_channels;
 
+	if (mlx5_dev_is_lightweight(mdev)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Setting num_doorbells requires full device initialization; reload the device first");
+		return -EOPNOTSUPP;
+	}
+
 	max_num_channels = mlx5e_get_max_num_channels(mdev);
 	if (val32 > max_num_channels) {
 		NL_SET_ERR_MSG_FMT_MOD(extack,

base-commit: f4377bf85887f57b59abb5479f7660a81ffe4449
-- 
2.44.0

Re: [PATCH net] net/mlx5: Only set num_doorbells on a fully initialized SF

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

 - What hardware the change was tested on. For driver fixes please
   mention the device (and if relevant firmware version) used for
   testing, or say that the change was not tested on real hardware.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.

Re: [PATCH net] net/mlx5: Only set num_doorbells on a fully initialized SF

[sashiko-bot]

> From: Cosmin Ratiu <cratiu@nvidia.com>
> 
> The validation for the num_doorbells devlink param rejects values
> greater than num_channels. For lightweight SFs, this ends up accessing
> a NULL priv->eq_table, leading to a crash.
> 
> Fix that by rejecting setting num_doorbells on uninitialized SFs.
> 
> Fixes: 11bbcfb7668c ("net/mlx5e: Use the 'num_doorbells' devlink param")
> Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
> Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261026084503.4122732-1-tariqt@nvidia.com?part=1

Re: [PATCH net] net/mlx5: Only set num_doorbells on a fully initialized SF

[Daniel Machon]

> From: Cosmin Ratiu <cratiu@nvidia.com>
> 
> The validation for the num_doorbells devlink param rejects values
> greater than num_channels. For lightweight SFs, this ends up accessing
> a NULL priv->eq_table, leading to a crash.
> 
> Fix that by rejecting setting num_doorbells on uninitialized SFs.
> 
> Fixes: 11bbcfb7668c ("net/mlx5e: Use the 'num_doorbells' devlink param")
> Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
> Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>

Reviewed-by: Daniel Machon <daniel.machon@microchip.com>

Re: [PATCH net] net/mlx5: Only set num_doorbells on a fully initialized SF

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Mon, 26 Oct 2026 10:45:03 +0200 you wrote:
> From: Cosmin Ratiu <cratiu@nvidia.com>
> 
> The validation for the num_doorbells devlink param rejects values
> greater than num_channels. For lightweight SFs, this ends up accessing
> a NULL priv->eq_table, leading to a crash.
> 
> Fix that by rejecting setting num_doorbells on uninitialized SFs.
> 
> [...]

Here is the summary with links:
  - [net] net/mlx5: Only set num_doorbells on a fully initialized SF
    https://git.kernel.org/netdev/net/c/fa503935c2d6

You are awesome, thank you!
-- 
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