* [PATCH] net: microchip: sparx5: reduce stack usage
@ 2023-02-17 9:58 Arnd Bergmann
2023-02-17 14:41 ` Alexander Lobakin
2023-02-20 11:00 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 3+ messages in thread
From: Arnd Bergmann @ 2023-02-17 9:58 UTC (permalink / raw)
To: Lars Povlsen, Steen Hegelund, Daniel Machon, UNGLinuxDriver,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: Arnd Bergmann, Horatiu Vultur, Yang Yingliang, linux-arm-kernel,
netdev, linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
The vcap_admin structures in vcap_api_next_lookup_advanced_test()
take several hundred bytes of stack frame, but when CONFIG_KASAN_STACK
is enabled, each one of them also has extra padding before and after
it, which ends up blowing the warning limit:
In file included from drivers/net/ethernet/microchip/vcap/vcap_api.c:3521:
drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c: In function 'vcap_api_next_lookup_advanced_test':
drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c:1954:1: error: the frame size of 1448 bytes is larger than 1400 bytes [-Werror=frame-larger-than=]
1954 | }
Reduce the total stack usage by replacing the five structures with
an array that only needs one pair of padding areas.
Fixes: 1f741f001160 ("net: microchip: sparx5: Add KUNIT tests for enabling/disabling chains")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
.../ethernet/microchip/vcap/vcap_api_kunit.c | 26 +++++++++----------
1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c b/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c
index 0a1d4d740567..c07f25e791c7 100644
--- a/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c
+++ b/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c
@@ -1876,53 +1876,51 @@ static void vcap_api_next_lookup_basic_test(struct kunit *test)
static void vcap_api_next_lookup_advanced_test(struct kunit *test)
{
- struct vcap_admin admin1 = {
+ struct vcap_admin admin[] = {
+ {
.vtype = VCAP_TYPE_IS0,
.vinst = 0,
.first_cid = 1000000,
.last_cid = 1199999,
.lookups = 6,
.lookups_per_instance = 2,
- };
- struct vcap_admin admin2 = {
+ }, {
.vtype = VCAP_TYPE_IS0,
.vinst = 1,
.first_cid = 1200000,
.last_cid = 1399999,
.lookups = 6,
.lookups_per_instance = 2,
- };
- struct vcap_admin admin3 = {
+ }, {
.vtype = VCAP_TYPE_IS0,
.vinst = 2,
.first_cid = 1400000,
.last_cid = 1599999,
.lookups = 6,
.lookups_per_instance = 2,
- };
- struct vcap_admin admin4 = {
+ }, {
.vtype = VCAP_TYPE_IS2,
.vinst = 0,
.first_cid = 8000000,
.last_cid = 8199999,
.lookups = 4,
.lookups_per_instance = 2,
- };
- struct vcap_admin admin5 = {
+ }, {
.vtype = VCAP_TYPE_IS2,
.vinst = 1,
.first_cid = 8200000,
.last_cid = 8399999,
.lookups = 4,
.lookups_per_instance = 2,
+ }
};
bool ret;
- vcap_test_api_init(&admin1);
- list_add_tail(&admin2.list, &test_vctrl.list);
- list_add_tail(&admin3.list, &test_vctrl.list);
- list_add_tail(&admin4.list, &test_vctrl.list);
- list_add_tail(&admin5.list, &test_vctrl.list);
+ vcap_test_api_init(&admin[0]);
+ list_add_tail(&admin[1].list, &test_vctrl.list);
+ list_add_tail(&admin[2].list, &test_vctrl.list);
+ list_add_tail(&admin[3].list, &test_vctrl.list);
+ list_add_tail(&admin[4].list, &test_vctrl.list);
ret = vcap_is_next_lookup(&test_vctrl, 1000000, 1001000);
KUNIT_EXPECT_EQ(test, false, ret);
--
2.39.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] net: microchip: sparx5: reduce stack usage
2023-02-17 9:58 [PATCH] net: microchip: sparx5: reduce stack usage Arnd Bergmann
@ 2023-02-17 14:41 ` Alexander Lobakin
2023-02-20 11:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Alexander Lobakin @ 2023-02-17 14:41 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Lars Povlsen, Steen Hegelund, Daniel Machon, UNGLinuxDriver,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Arnd Bergmann, Horatiu Vultur, Yang Yingliang, linux-arm-kernel,
netdev, linux-kernel
From: Arnd Bergmann <arnd@kernel.org>
Date: Fri, 17 Feb 2023 10:58:06 +0100
> From: Arnd Bergmann <arnd@arndb.de>
>
> The vcap_admin structures in vcap_api_next_lookup_advanced_test()
> take several hundred bytes of stack frame, but when CONFIG_KASAN_STACK
> is enabled, each one of them also has extra padding before and after
> it, which ends up blowing the warning limit:
>
> In file included from drivers/net/ethernet/microchip/vcap/vcap_api.c:3521:
> drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c: In function 'vcap_api_next_lookup_advanced_test':
> drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c:1954:1: error: the frame size of 1448 bytes is larger than 1400 bytes [-Werror=frame-larger-than=]
> 1954 | }
>
> Reduce the total stack usage by replacing the five structures with
> an array that only needs one pair of padding areas.
>
> Fixes: 1f741f001160 ("net: microchip: sparx5: Add KUNIT tests for enabling/disabling chains")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
I'd suggest the driver authors to reduce the stack usage by moving big
data to the heap where possible tho. Otherwise, there probably will be
a new warning eventually one day.
> ---
> .../ethernet/microchip/vcap/vcap_api_kunit.c | 26 +++++++++----------
> 1 file changed, 12 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c b/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c
> index 0a1d4d740567..c07f25e791c7 100644
> --- a/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c
> +++ b/drivers/net/ethernet/microchip/vcap/vcap_api_kunit.c
> @@ -1876,53 +1876,51 @@ static void vcap_api_next_lookup_basic_test(struct kunit *test)
>
> static void vcap_api_next_lookup_advanced_test(struct kunit *test)
> {
> - struct vcap_admin admin1 = {
> + struct vcap_admin admin[] = {
> + {
> .vtype = VCAP_TYPE_IS0,
> .vinst = 0,
> .first_cid = 1000000,
> .last_cid = 1199999,
> .lookups = 6,
> .lookups_per_instance = 2,
> - };
> - struct vcap_admin admin2 = {
> + }, {
> .vtype = VCAP_TYPE_IS0,
> .vinst = 1,
> .first_cid = 1200000,
> .last_cid = 1399999,
> .lookups = 6,
> .lookups_per_instance = 2,
> - };
> - struct vcap_admin admin3 = {
> + }, {
> .vtype = VCAP_TYPE_IS0,
> .vinst = 2,
> .first_cid = 1400000,
> .last_cid = 1599999,
> .lookups = 6,
> .lookups_per_instance = 2,
> - };
> - struct vcap_admin admin4 = {
> + }, {
> .vtype = VCAP_TYPE_IS2,
> .vinst = 0,
> .first_cid = 8000000,
> .last_cid = 8199999,
> .lookups = 4,
> .lookups_per_instance = 2,
> - };
> - struct vcap_admin admin5 = {
> + }, {
> .vtype = VCAP_TYPE_IS2,
> .vinst = 1,
> .first_cid = 8200000,
> .last_cid = 8399999,
> .lookups = 4,
> .lookups_per_instance = 2,
> + }
> };
> bool ret;
>
> - vcap_test_api_init(&admin1);
> - list_add_tail(&admin2.list, &test_vctrl.list);
> - list_add_tail(&admin3.list, &test_vctrl.list);
> - list_add_tail(&admin4.list, &test_vctrl.list);
> - list_add_tail(&admin5.list, &test_vctrl.list);
> + vcap_test_api_init(&admin[0]);
> + list_add_tail(&admin[1].list, &test_vctrl.list);
> + list_add_tail(&admin[2].list, &test_vctrl.list);
> + list_add_tail(&admin[3].list, &test_vctrl.list);
> + list_add_tail(&admin[4].list, &test_vctrl.list);
>
> ret = vcap_is_next_lookup(&test_vctrl, 1000000, 1001000);
> KUNIT_EXPECT_EQ(test, false, ret);
Thanks,
Olek
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] net: microchip: sparx5: reduce stack usage
2023-02-17 9:58 [PATCH] net: microchip: sparx5: reduce stack usage Arnd Bergmann
2023-02-17 14:41 ` Alexander Lobakin
@ 2023-02-20 11:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-02-20 11:00 UTC (permalink / raw)
To: Arnd Bergmann
Cc: lars.povlsen, Steen.Hegelund, daniel.machon, UNGLinuxDriver,
davem, edumazet, kuba, pabeni, arnd, horatiu.vultur,
yangyingliang, linux-arm-kernel, netdev, linux-kernel
Hello:
This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:
On Fri, 17 Feb 2023 10:58:06 +0100 you wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The vcap_admin structures in vcap_api_next_lookup_advanced_test()
> take several hundred bytes of stack frame, but when CONFIG_KASAN_STACK
> is enabled, each one of them also has extra padding before and after
> it, which ends up blowing the warning limit:
>
> [...]
Here is the summary with links:
- net: microchip: sparx5: reduce stack usage
https://git.kernel.org/netdev/net-next/c/129ff4de58ff
You are awesome, thank you!
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2023-02-17 9:58 [PATCH] net: microchip: sparx5: reduce stack usage Arnd Bergmann
2023-02-17 14:41 ` Alexander Lobakin
2023-02-20 11:00 ` patchwork-bot+netdevbpf
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