diff mbox series

[net-next,2/2] mlxsw: spectrum_ethtool: Fix -Wformat-truncation warning

Message ID e7779667560002877280bd0b9d99cc23677ee293.1696600763.git.petrm@nvidia.com (mailing list archive)
State Accepted
Commit 392ce2abb0cef182f026324b208d1856e58ecac8
Delegated to: Netdev Maintainers
Headers show
Series mlxsw: Fix -Wformat-truncation warnings | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1362 this patch: 1362
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang fail Errors and warnings before: 17 this patch: 17
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 19 this patch: 17
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Petr Machata Oct. 6, 2023, 2:43 p.m. UTC 
From: Ido Schimmel <idosch@nvidia.com>

Ethtool stats strings cannot be longer than 32 characters
('ETH_GSTRING_LEN'), including the terminating null byte. The format
string '%.29s_%.1d' can exceed this limitation if the per-TC counter
name exceeds 28 characters. Together with the underscore, the two digits
of the TC (bounded at 16) and the terminating null byte, more than 32
characters will be used.

Fix this by bounding the counter name at 28 characters which suppresses
the following build warning [1]. This does not affect ethtool output
since the longest counter name does not exceed this limitation.

[1]
drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c: In function ‘mlxsw_sp_port_get_strings’:
drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c:622:58: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
  622 |                 snprintf(*p, ETH_GSTRING_LEN, "%.29s_%.1d",
      |                                                          ^
In function ‘mlxsw_sp_port_get_tc_strings’,
    inlined from ‘mlxsw_sp_port_get_strings’ at drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c:677:4:
drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c:622:17: note: ‘snprintf’ output between 3 and 33 bytes into a destination of size 32
  622 |                 snprintf(*p, ETH_GSTRING_LEN, "%.29s_%.1d",
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  623 |                          mlxsw_sp_port_hw_tc_stats[i].str, tc);
      |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c: In function ‘mlxsw_sp_port_get_strings’:
drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c:622:58: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
  622 |                 snprintf(*p, ETH_GSTRING_LEN, "%.29s_%.1d",
      |                                                          ^
In function ‘mlxsw_sp_port_get_tc_strings’,
    inlined from ‘mlxsw_sp_port_get_strings’ at drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c:677:4:
drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c:622:17: note: ‘snprintf’ output between 3 and 33 bytes into a destination of size 32
  622 |                 snprintf(*p, ETH_GSTRING_LEN, "%.29s_%.1d",
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  623 |                          mlxsw_sp_port_hw_tc_stats[i].str, tc);
      |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c
index 472830d07ac1..0f29e9c19411 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ethtool.c
@@ -619,7 +619,7 @@  static void mlxsw_sp_port_get_tc_strings(u8 **p, int tc)
 	int i;
 
 	for (i = 0; i < MLXSW_SP_PORT_HW_TC_STATS_LEN; i++) {
-		snprintf(*p, ETH_GSTRING_LEN, "%.29s_%.1d",
+		snprintf(*p, ETH_GSTRING_LEN, "%.28s_%d",
 			 mlxsw_sp_port_hw_tc_stats[i].str, tc);
 		*p += ETH_GSTRING_LEN;
 	}