2023-02-21 13:57:28

by Jochen Henneberg

Subject: [PATCH net] net: stmmac: Premature loop termination check was ignored

The premature loop termination check makes sense only in case of the
jump to read_again where the count may have been updated. But
read_again did not include the check.

Signed-off-by: Jochen Henneberg <[email protected]>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 1a5b8dab5e9b..de98c009866a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5031,10 +5031,10 @@ static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
len = 0;
}

+read_again:
if (count >= limit)
break;

-read_again:
buf1_len = 0;
entry = next_entry;
buf = &rx_q->buf_pool[entry];
@@ -5221,10 +5221,10 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
len = 0;
}

+read_again:
if (count >= limit)
break;

-read_again:
buf1_len = 0;
buf2_len = 0;
entry = next_entry;
--
2.39.2

2023-02-21 16:42:28

by Simon Horman

Subject: Re: [PATCH net] net: stmmac: Premature loop termination check was ignored

On Tue, Feb 21, 2023 at 02:38:27PM +0100, Jochen Henneberg wrote:
>
> The premature loop termination check makes sense only in case of the
> jump to read_again where the count may have been updated. But
> read_again did not include the check.

I think a fixes tag appropriate here.

> Signed-off-by: Jochen Henneberg <[email protected]>
> ---
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

Code change makes sense to me.

> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 1a5b8dab5e9b..de98c009866a 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -5031,10 +5031,10 @@ static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
> len = 0;
> }
>
> +read_again:
> if (count >= limit)
> break;
>
> -read_again:
> buf1_len = 0;
> entry = next_entry;
> buf = &rx_q->buf_pool[entry];
> @@ -5221,10 +5221,10 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
> len = 0;
> }
>
> +read_again:
> if (count >= limit)
> break;
>
> -read_again:
> buf1_len = 0;
> buf2_len = 0;
> entry = next_entry;
> --
> 2.39.2
>

2023-02-21 19:38:01

by Jochen Henneberg

Subject: Re: [PATCH net V2] net: stmmac: Premature loop termination check was ignored

The premature loop termination check makes sense only in case of the
jump to read_again where the count may have been updated. But
read_again did not include the check.

Fixes: bba2556efad6 (net: stmmac: Enable RX via AF_XDP zero-copy)
Fixes: ec222003bd94 (net: stmmac: Prepare to add Split Header support)
Signed-off-by: Jochen Henneberg <[email protected]>
---
V2: Added fixes tags for both commits that introduced the issue

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 1a5b8dab5e9b..de98c009866a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5031,10 +5031,10 @@ static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
len = 0;
}

+read_again:
if (count >= limit)
break;

-read_again:
buf1_len = 0;
entry = next_entry;
buf = &rx_q->buf_pool[entry];
@@ -5221,10 +5221,10 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
len = 0;
}

+read_again:
if (count >= limit)
break;

-read_again:
buf1_len = 0;
buf2_len = 0;
entry = next_entry;
--
2.39.2

2023-02-21 19:41:14

by Jakub Kicinski

Subject: Re: [PATCH net V2] net: stmmac: Premature loop termination check was ignored

On Tue, 21 Feb 2023 20:35:25 +0100 Jochen Henneberg wrote:
> The premature loop termination check makes sense only in case of the
> jump to read_again where the count may have been updated. But
> read_again did not include the check.
>
> Fixes: bba2556efad6 (net: stmmac: Enable RX via AF_XDP zero-copy)
> Fixes: ec222003bd94 (net: stmmac: Prepare to add Split Header support)
> Signed-off-by: Jochen Henneberg <[email protected]>

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