[PATCH] staging: octeon: Add prevent NAPI from scheduling

[PATCH] staging: octeon: Add prevent NAPI from scheduling

[Marina Makienko]

Code inspection shows that this can
only be triggered by calling napi_enable() without
napi_disable().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Marina Makienko <makienko@ispras.ru>
---
 drivers/staging/octeon/ethernet-rx.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/octeon/ethernet-rx.c b/drivers/staging/octeon/ethernet-rx.c
index 34afc16..db81613 100644
--- a/drivers/staging/octeon/ethernet-rx.c
+++ b/drivers/staging/octeon/ethernet-rx.c
@@ -560,4 +560,5 @@ void cvm_oct_rx_shutdown(void)
 	/* Shutdown all of the NAPIs */
 	for_each_possible_cpu(i)
 		netif_napi_del(&cvm_oct_napi[i].napi);
+		napi_disable(&cvm_oct_napi[i].napi);
 }
-- 
1.7.7

Re: [PATCH] staging: octeon: Add prevent NAPI from scheduling

[David Daney]

On 08/20/2012 03:41 AM, Marina Makienko wrote:
> Code inspection shows that this can
> only be triggered by calling napi_enable() without
> napi_disable().
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Marina Makienko <makienko@ispras.ru>
> ---
>   drivers/staging/octeon/ethernet-rx.c |    1 +
>   1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/staging/octeon/ethernet-rx.c b/drivers/staging/octeon/ethernet-rx.c
> index 34afc16..db81613 100644
> --- a/drivers/staging/octeon/ethernet-rx.c
> +++ b/drivers/staging/octeon/ethernet-rx.c
> @@ -560,4 +560,5 @@ void cvm_oct_rx_shutdown(void)
>   	/* Shutdown all of the NAPIs */
>   	for_each_possible_cpu(i)
>   		netif_napi_del(&cvm_oct_napi[i].napi);
> +		napi_disable(&cvm_oct_napi[i].napi);


Does the order of netif_napi_del() and napi_disable() matter?  If so, 
does this patch have the correct ordering?

I don't really want to apply the patch until we know the answer to these 
two questions.

David Daney

Re: [PATCH] staging: octeon: Add prevent NAPI from scheduling

[Max Filippov]

On Mon, Aug 20, 2012 at 2:41 PM, Marina Makienko <makienko@ispras.ru> wrote:
> Code inspection shows that this can
> only be triggered by calling napi_enable() without
> napi_disable().
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Marina Makienko <makienko@ispras.ru>
> ---
>  drivers/staging/octeon/ethernet-rx.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/staging/octeon/ethernet-rx.c b/drivers/staging/octeon/ethernet-rx.c
> index 34afc16..db81613 100644
> --- a/drivers/staging/octeon/ethernet-rx.c
> +++ b/drivers/staging/octeon/ethernet-rx.c
> @@ -560,4 +560,5 @@ void cvm_oct_rx_shutdown(void)
>         /* Shutdown all of the NAPIs */
>         for_each_possible_cpu(i)
>                 netif_napi_del(&cvm_oct_napi[i].napi);
> +               napi_disable(&cvm_oct_napi[i].napi);
>  }

Looks like napi_disable is meant to be inside for_each_possible_cpu loop,
but curly braces are missing.

-- 
Thanks.
-- Max

[PATCH] staging: octeon: Add prevent NAPI from scheduling IN-REPLY-TO:

[Marina Makienko]

There are netif_napi_add() and napi_enable() in for_each_possible_cpu
loop in function cvm_oct_rx_initialize(). So it's logical to add
napi_disable() in for_each_possible_cpu loop in function
cvm_oct_rx_shutdown().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Marina Makienko <makienko@ispras.ru>
---
 drivers/staging/octeon/ethernet-rx.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/octeon/ethernet-rx.c b/drivers/staging/octeon/ethernet-rx.c
index 34afc16..e5b62fc 100644
--- a/drivers/staging/octeon/ethernet-rx.c
+++ b/drivers/staging/octeon/ethernet-rx.c
@@ -558,6 +558,8 @@ void cvm_oct_rx_shutdown(void)
 {
 	int i;
 	/* Shutdown all of the NAPIs */
-	for_each_possible_cpu(i)
+	for_each_possible_cpu(i) {
 		netif_napi_del(&cvm_oct_napi[i].napi);
+		napi_disable(&cvm_oct_napi[i].napi);
+	}
 }
-- 
1.7.7

[PATCH] staging: octeon: Add prevent NAPI from scheduling IN-REPLY-TO:

[Marina Makienko]

Please ignore previous message.

-- 
1.7.7