From 1bbdb81a98363fd5cd0c2ac16ad5346bdf814dff Mon Sep 17 00:00:00 2001 From: Carolina Jubran Date: Tue, 22 Jul 2025 12:13:29 +0300 Subject: 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: 566e8f108fc7 ("devlink: Extend devlink rate API with traffic classes bandwidth management") Reported-by: Arnd Bergmann Closes: https://lore.kernel.org/netdev/20250708160652.1810573-1-arnd@kernel.org/ Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202507171943.W7DJcs6Y-lkp@intel.com/ Suggested-by: Jakub Kicinski Signed-off-by: Carolina Jubran Tested-by: Carolina Jubran Signed-off-by: Tariq Toukan Reviewed-by: Jiri Pirko Link: https://patch.msgid.link/1753175609-330621-1-git-send-email-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- include/uapi/linux/devlink.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h index e72bcc239afd..9fcb25a0f447 100644 --- a/include/uapi/linux/devlink.h +++ b/include/uapi/linux/devlink.h @@ -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 */ -- cgit v1.2.3