linux/net/devlink
Carolina Jubran 1bbdb81a98 devlink: Fix excessive stack usage in rate TC bandwidth parsing
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>
2025-07-23 17:07:35 -07:00
..
Makefile devlink: move devlink_notify_register/unregister() to dev.c 2023-08-28 08:02:24 -07:00
core.c devlink: fix xa_alloc_cyclic() error handling 2025-03-19 09:57:36 +00:00
dev.c devlink: add value check to devlink_info_version_put() 2025-04-15 07:36:31 -07:00
devl_internal.h devlink: introduce devlink_nl_put_u64() 2024-10-29 16:52:56 -07:00
dpipe.c devlink: use devlink_nl_put_u64() helper 2024-10-29 16:52:56 -07:00
health.c devlink: use DEVLINK_VAR_ATTR_TYPE_* instead of NLA_* in fmsg 2025-05-06 18:21:11 -07:00
linecard.c devlink: introduce a helper for netlink multicast send 2023-12-19 15:31:40 +01:00
netlink.c devlink: Fix devlink parallel commands processing 2024-03-13 08:31:40 +00:00
netlink_gen.c devlink: Fix excessive stack usage in rate TC bandwidth parsing 2025-07-23 17:07:35 -07:00
netlink_gen.h devlink: Fix excessive stack usage in rate TC bandwidth parsing 2025-07-23 17:07:35 -07:00
param.c devlink: Add new "clock_id" generic device param 2025-07-09 19:08:52 -07:00
port.c devlink: Improve the port attributes description 2025-01-02 17:10:57 -08:00
rate.c devlink: Fix excessive stack usage in rate TC bandwidth parsing 2025-07-23 17:07:35 -07:00
region.c devlink: region: snapshot IDs: consolidate error values 2024-10-29 16:52:57 -07:00
resource.c devlink: remove unused devlink_resource_register() 2024-10-29 16:52:57 -07:00
sb.c devlink: rename netlink callback to be aligned with the generated ones 2023-10-23 16:12:47 -07:00
trap.c devlink: use devlink_nl_put_u64() helper 2024-10-29 16:52:56 -07:00