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devlink: Fix excessive stack usage in rate TC bandwidth parsing

Browse source 
The devlink_nl_rate_tc_bw_parse function uses a large stack array for
devlink attributes, which triggers a warning about excessive stack
usage:

net/devlink/rate.c: In function 'devlink_nl_rate_tc_bw_parse':
net/devlink/rate.c:382:1: error: the frame size of 1648 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

Introduce a separate attribute set specifically for rate TC bandwidth
parsing that only contains the two attributes actually used: index
and bandwidth. This reduces the stack array from DEVLINK_ATTR_MAX
entries to just 2 entries, solving the stack usage issue.

Update devlink selftest to use the new 'index' and 'bw' attribute names
consistent with the YAML spec.

Example usage with ynl with the new spec:

    ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
      --do rate-set --json '{
      "bus-name": "pci",
      "dev-name": "0000:08:00.0",
      "port-index": 1,
      "rate-tc-bws": [
        {"index": 0, "bw": 50},
        {"index": 1, "bw": 50},
        {"index": 2, "bw": 0},
        {"index": 3, "bw": 0},
        {"index": 4, "bw": 0},
        {"index": 5, "bw": 0},
        {"index": 6, "bw": 0},
        {"index": 7, "bw": 0}
      ]
    }'

    ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
      --do rate-get --json '{
      "bus-name": "pci",
      "dev-name": "0000:08:00.0",
      "port-index": 1
    }'

    output for rate-get:
    {'bus-name': 'pci',
     'dev-name': '0000:08:00.0',
     'port-index': 1,
     'rate-tc-bws': [{'bw': 50, 'index': 0},
                     {'bw': 50, 'index': 1},
                     {'bw': 0, 'index': 2},
                     {'bw': 0, 'index': 3},
                     {'bw': 0, 'index': 4},
                     {'bw': 0, 'index': 5},
                     {'bw': 0, 'index': 6},
                     {'bw': 0, 'index': 7}],
     'rate-tx-max': 0,
     'rate-tx-priority': 0,
     'rate-tx-share': 0,
     'rate-tx-weight': 0,
     'rate-type': 'leaf'}

Fixes: 566e8f108f ("devlink: Extend devlink rate API with traffic classes bandwidth management")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Closes: https://lore.kernel.org/netdev/20250708160652.1810573-1-arnd@kernel.org/
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202507171943.W7DJcs6Y-lkp@intel.com/
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Tested-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://patch.msgid.link/1753175609-330621-1-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Carolina Jubran 2025-07-22 12:13:29 +03:00 • committed by Jakub Kicinski
parent 56613001df
commit 1bbdb81a98
6 changed files with 42 additions and 39 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

26
Documentation/netlink/specs/devlink.yaml
View file

@ -853,18 +853,6 @@ attribute-sets:
type: nest
multi-attr: true
nested-attributes: dl-rate-tc-bws
-
name: rate-tc-index
type: u8
checks:
max: rate-tc-index-max
-
name: rate-tc-bw
type: u32
doc: |
Specifies the bandwidth share assigned to the Traffic Class.
The bandwidth for the traffic class is determined
in proportion to the sum of the shares of all configured classes.
-
name: dl-dev-stats
subset-of: devlink
@ -1271,12 +1259,20 @@ attribute-sets:
type: flag
-
name: dl-rate-tc-bws
subset-of: devlink
name-prefix: devlink-rate-tc-attr-
attributes:
-
name: rate-tc-index
name: index
type: u8
checks:
max: rate-tc-index-max
-
name: rate-tc-bw
name: bw
type: u32
doc: |
Specifies the bandwidth share assigned to the Traffic Class.
The bandwidth for the traffic class is determined
in proportion to the sum of the shares of all configured classes.
operations:
enum-model: directional

11
include/uapi/linux/devlink.h
View file

@ -635,8 +635,6 @@ enum devlink_attr {
DEVLINK_ATTR_REGION_DIRECT, /* flag */
DEVLINK_ATTR_RATE_TC_BWS, /* nested */
DEVLINK_ATTR_RATE_TC_INDEX, /* u8 */
DEVLINK_ATTR_RATE_TC_BW, /* u32 */
/* Add new attributes above here, update the spec in
* Documentation/netlink/specs/devlink.yaml and re-generate
@ -647,6 +645,15 @@ enum devlink_attr {
DEVLINK_ATTR_MAX = __DEVLINK_ATTR_MAX - 1
};
enum devlink_rate_tc_attr {
DEVLINK_RATE_TC_ATTR_UNSPEC,
DEVLINK_RATE_TC_ATTR_INDEX, /* u8 */
DEVLINK_RATE_TC_ATTR_BW, /* u32 */
__DEVLINK_RATE_TC_ATTR_MAX,
DEVLINK_RATE_TC_ATTR_MAX = __DEVLINK_RATE_TC_ATTR_MAX - 1
};
/* Mapping between internal resource described by the field and system
* structure
*/

6
net/devlink/netlink_gen.c
View file

@ -45,9 +45,9 @@ const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_
[DEVLINK_PORT_FN_ATTR_CAPS] = NLA_POLICY_BITFIELD32(15),
};
const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_ATTR_RATE_TC_BW + 1] = {
[DEVLINK_ATTR_RATE_TC_INDEX] = NLA_POLICY_MAX(NLA_U8, DEVLINK_RATE_TC_INDEX_MAX),
[DEVLINK_ATTR_RATE_TC_BW] = { .type = NLA_U32, },
const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_RATE_TC_ATTR_BW + 1] = {
[DEVLINK_RATE_TC_ATTR_INDEX] = NLA_POLICY_MAX(NLA_U8, DEVLINK_RATE_TC_INDEX_MAX),
[DEVLINK_RATE_TC_ATTR_BW] = { .type = NLA_U32, },
};
const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1] = {

2
net/devlink/netlink_gen.h
View file

@ -13,7 +13,7 @@
/* Common nested types */
extern const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_CAPS + 1];
extern const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_ATTR_RATE_TC_BW + 1];
extern const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_RATE_TC_ATTR_BW + 1];
extern const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1];
/* Ops table for devlink */

20
net/devlink/rate.c
View file

@ -90,8 +90,8 @@ static int devlink_rate_put_tc_bws(struct sk_buff *msg, u32 *tc_bw)
if (!nla_tc_bw)
return -EMSGSIZE;
if (nla_put_u8(msg, DEVLINK_ATTR_RATE_TC_INDEX, i) ||
nla_put_u32(msg, DEVLINK_ATTR_RATE_TC_BW, tc_bw[i]))
if (nla_put_u8(msg, DEVLINK_RATE_TC_ATTR_INDEX, i) ||
nla_put_u32(msg, DEVLINK_RATE_TC_ATTR_BW, tc_bw[i]))
goto nla_put_failure;
nla_nest_end(msg, nla_tc_bw);
@ -346,26 +346,26 @@ static int devlink_nl_rate_tc_bw_parse(struct nlattr *parent_nest, u32 *tc_bw,
unsigned long *bitmap,
struct netlink_ext_ack *extack)
{
struct nlattr *tb[DEVLINK_ATTR_MAX + 1];
struct nlattr *tb[DEVLINK_RATE_TC_ATTR_MAX + 1];
u8 tc_index;
int err;
err = nla_parse_nested(tb, DEVLINK_ATTR_MAX, parent_nest,
err = nla_parse_nested(tb, DEVLINK_RATE_TC_ATTR_MAX, parent_nest,
devlink_dl_rate_tc_bws_nl_policy, extack);
if (err)
return err;
if (!tb[DEVLINK_ATTR_RATE_TC_INDEX]) {
if (!tb[DEVLINK_RATE_TC_ATTR_INDEX]) {
NL_SET_ERR_ATTR_MISS(extack, parent_nest,
DEVLINK_ATTR_RATE_TC_INDEX);
DEVLINK_RATE_TC_ATTR_INDEX);
return -EINVAL;
}
tc_index = nla_get_u8(tb[DEVLINK_ATTR_RATE_TC_INDEX]);
tc_index = nla_get_u8(tb[DEVLINK_RATE_TC_ATTR_INDEX]);
if (!tb[DEVLINK_ATTR_RATE_TC_BW]) {
if (!tb[DEVLINK_RATE_TC_ATTR_BW]) {
NL_SET_ERR_ATTR_MISS(extack, parent_nest,
DEVLINK_ATTR_RATE_TC_BW);
DEVLINK_RATE_TC_ATTR_BW);
return -EINVAL;
}
@ -376,7 +376,7 @@ static int devlink_nl_rate_tc_bw_parse(struct nlattr *parent_nest, u32 *tc_bw,
return -EINVAL;
}
tc_bw[tc_index] = nla_get_u32(tb[DEVLINK_ATTR_RATE_TC_BW]);
tc_bw[tc_index] = nla_get_u32(tb[DEVLINK_RATE_TC_ATTR_BW]);
return 0;
}

16
tools/testing/selftests/drivers/net/hw/devlink_rate_tc_bw.py
View file

@ -208,14 +208,14 @@ def setup_devlink_rate(cfg):
"port-index": port_index,
"rate-tx-max": 125000000,
"rate-tc-bws": [
{"rate-tc-index": 0, "rate-tc-bw": 0},
{"rate-tc-index": 1, "rate-tc-bw": 0},
{"rate-tc-index": 2, "rate-tc-bw": 0},
{"rate-tc-index": 3, "rate-tc-bw": 20},
{"rate-tc-index": 4, "rate-tc-bw": 80},
{"rate-tc-index": 5, "rate-tc-bw": 0},
{"rate-tc-index": 6, "rate-tc-bw": 0},
{"rate-tc-index": 7, "rate-tc-bw": 0},
{"index": 0, "bw": 0},
{"index": 1, "bw": 0},
{"index": 2, "bw": 0},
{"index": 3, "bw": 20},
{"index": 4, "bw": 80},
{"index": 5, "bw": 0},
{"index": 6, "bw": 0},
{"index": 7, "bw": 0},
]
})
except NlError as exc: