LinuxLists.cc - [PATCH] net: stmmac:fix system hang when setting up tag

2023-04-13 13:50:33

Subject: [PATCH] net: stmmac:fix system hang when setting up tag_8021q VLAN for DSA ports

2023-04-13 17:04:48

Subject: Re: [PATCH] net: stmmac:fix system hang when setting up tag_8021q VLAN for DSA ports

On 4/13/2023 6:38 AM, Yan Wang wrote:
> The system hang because of dsa_tag_8021q_port_setup()->
> stmmac_vlan_rx_add_vid().
>
> I found in stmmac_drv_probe() that cailing pm_runtime_put()
> disabled the clock.
>
> First, when the kernel is compiled with CONFIG_PM=y,The stmmac's
> resume/suspend is active.
>
> Secondly,stmmac as DSA master,the dsa_tag_8021q_port_setup() function
> will callback stmmac_vlan_rx_add_vid when DSA dirver starts. However,
> The system is hanged for the stmmac_vlan_rx_add_vid() accesses its
> registers after stmmac's clock is closed.
>

And access to the registers basically just waits because its clock is
stopped?

> I would suggest adding the pm_runtime_resume_and_get() to the
> stmmac_vlan_rx_add_vid().This guarantees that resuming clock output
> while in use.
>

It feels a bit odd to need this within the VLAN function, but these can
be entered at an odd time where its possible that the clock has been
closed... Ok.

> Signed-off-by: Yan Wang <[email protected]>
> ---

Reviewed-by: Jacob Keller <[email protected]>

> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index d7fcab057032..f9cd063f1fe3 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -6350,6 +6350,10 @@ static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid
> bool is_double = false;
> int ret;
>
> + ret = pm_runtime_resume_and_get(priv->device);
> + if (ret < 0)
> + return ret;
> +
> if (be16_to_cpu(proto) == ETH_P_8021AD)
> is_double = true;
>
> @@ -6357,16 +6361,18 @@ static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid
> ret = stmmac_vlan_update(priv, is_double);
> if (ret) {
> clear_bit(vid, priv->active_vlans);
> - return ret;
> + goto err_pm_put;
> }
>
> if (priv->hw->num_vlan) {
> ret = stmmac_add_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
> if (ret)
> - return ret;
> + goto err_pm_put;
> }
> +err_pm_put:
> + pm_runtime_put(priv->device);
>
> - return 0;
> + return ret;
> }
>
> static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vid)

2023-04-19 14:17:35

by Yan Wang

[permalink] [raw]

Subject: [PATCH net-next v6] net: stmmac:fix system hang when setting up tag_8021q VLAN for DSA ports

The system hang because of dsa_tag_8021q_port_setup()->
stmmac_vlan_rx_add_vid().

I found in stmmac_drv_probe() that cailing pm_runtime_put()
disabled the clock.

First, when the kernel is compiled with CONFIG_PM=y,The stmmac's
resume/suspend is active.

Secondly,stmmac as DSA master,the dsa_tag_8021q_port_setup() function
will callback stmmac_vlan_rx_add_vid when DSA dirver starts. However,
The system is hanged for the stmmac_vlan_rx_add_vid() accesses its
registers after stmmac's clock is closed.

I would suggest adding the pm_runtime_resume_and_get() to the
stmmac_vlan_rx_add_vid().This guarantees that resuming clock output
while in use.

Fixes: b3dcb3127786 ("net: stmmac: correct clocks enabled in stmmac_vlan_rx_kill_vid()")
Reviewed-by: Jacob Keller <[email protected]>
Signed-off-by: Yan Wang <[email protected]>
---
v6:
- Add Reviewed Signature
v5: https://lore.kernel.org/netdev/KL1PR01MB544863D839654F0EC9485894E69C9@KL1PR01MB5448.apcprd01.prod.exchangelabs.com/
- Add version tags.
v4: https://lore.kernel.org/netdev/KL1PR01MB5448C7BF5A7AAC1CBCD5C36AE6989@KL1PR01MB5448.apcprd01.prod.exchangelabs.com/
- Fixed email address,but The Version number is wrong.
v3: https://lore.kernel.org/netdev/KL1PR01MB544872920F00149E3BDDC7ECE6999@KL1PR01MB5448.apcprd01.prod.exchangelabs.com/
- Fixed the Fixes tag,but Missing version change log.
v2: https://lore.kernel.org/netdev/KL1PR01MB54482D50B5C8713A2CA697DFE6999@KL1PR01MB5448.apcprd01.prod.exchangelabs.com/
- Add a error fixed tag.
v1: https://lore.kernel.org/netdev/KL1PR01MB5448020DE191340AE64530B0E6989@KL1PR01MB5448.apcprd01.prod.exchangelabs.com/
- the Subject is set incorrectly
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index d7fcab057032..f9cd063f1fe3 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -6350,6 +6350,10 @@ static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid
bool is_double = false;
int ret;

+ ret = pm_runtime_resume_and_get(priv->device);
+ if (ret < 0)
+ return ret;
+
if (be16_to_cpu(proto) == ETH_P_8021AD)
is_double = true;

@@ -6357,16 +6361,18 @@ static int stmmac_vlan_rx_add_vid(struct net_device *ndev, __be16 proto, u16 vid
ret = stmmac_vlan_update(priv, is_double);
if (ret) {
clear_bit(vid, priv->active_vlans);
- return ret;
+ goto err_pm_put;
}

if (priv->hw->num_vlan) {
ret = stmmac_add_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
if (ret)
- return ret;
+ goto err_pm_put;
}
+err_pm_put:
+ pm_runtime_put(priv->device);

- return 0;
+ return ret;
}

static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vid)
--
2.17.1

2023-04-21 11:06:45

by patchwork-bot+netdevbpf

[permalink] [raw]

Subject: Re: [PATCH net-next v6] net: stmmac:fix system hang when setting up tag_8021q VLAN for DSA ports

Hello:

This patch was applied to netdev/net-next.git (main)
by David S. Miller <[email protected]>:

On Wed, 19 Apr 2023 22:13:46 +0800 you wrote:
> The system hang because of dsa_tag_8021q_port_setup()->
> stmmac_vlan_rx_add_vid().
>
> I found in stmmac_drv_probe() that cailing pm_runtime_put()
> disabled the clock.
>
> First, when the kernel is compiled with CONFIG_PM=y,The stmmac's
> resume/suspend is active.
>
> [...]

Here is the summary with links:
- [net-next,v6] net: stmmac:fix system hang when setting up tag_8021q VLAN for DSA ports
https://git.kernel.org/netdev/net-next/c/35226750f7ab

You are awesome, thank you!
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