diff mbox series

[net-next,10/10] mlxsw: core_thermal: Fix -Wformat-truncation warning

Message ID 583a70c6dbe75e6bf0c2c58abbb3470a860d2dc3.1722345311.git.petrm@nvidia.com (mailing list archive)
State Accepted
Commit b0d21321140ce9a3cbdf877a4902cce2b596f282
Delegated to: Netdev Maintainers
Headers show
Series mlxsw: core_thermal: Small cleanups | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
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: 42 this patch: 42
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 43 this patch: 43
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 success Errors and warnings before: 44 this patch: 43
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Petr Machata July 30, 2024, 1:58 p.m. UTC 
From: Ido Schimmel <idosch@nvidia.com>

The name of a thermal zone device cannot be longer than 19 characters
('THERMAL_NAME_LENGTH - 1'). The format string 'mlxsw-lc%d-module%d' can
exceed this limitation if the maximum number of line cards cannot be
represented using a single digit and the maximum number of transceiver
modules cannot be represented using two digits.

This is not the case with current systems nor future ones. Therefore,
increase the size of the result buffer beyond 'THERMAL_NAME_LENGTH' and
suppress the following build warning [1].

If this limitation is ever exceeded, we will know about it since the
thermal core validates the thermal device's name during registration.

[1]
drivers/net/ethernet/mellanox/mlxsw/core_thermal.c: In function ‘mlxsw_thermal_modules_init.part.0’:
drivers/net/ethernet/mellanox/mlxsw/core_thermal.c:418:70: error: ‘%d’ directive output may be truncated writing between 1 and 3 bytes into a region of size between 2 and 4 [-Werror=format-truncation=]
  418 |                 snprintf(tz_name, sizeof(tz_name), "mlxsw-lc%d-module%d",
      |                                                                      ^~
In function ‘mlxsw_thermal_module_tz_init’,
    inlined from ‘mlxsw_thermal_module_init’ at drivers/net/ethernet/mellanox/mlxsw/core_thermal.c:465:9,
    inlined from ‘mlxsw_thermal_modules_init.part.0’ at drivers/net/ethernet/mellanox/mlxsw/core_thermal.c:500:9:
drivers/net/ethernet/mellanox/mlxsw/core_thermal.c:418:52: note: directive argument in the range [1, 256]
  418 |                 snprintf(tz_name, sizeof(tz_name), "mlxsw-lc%d-module%d",
      |                                                    ^~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/mellanox/mlxsw/core_thermal.c:418:17: note: ‘snprintf’ output between 18 and 22 bytes into a destination of size 20
  418 |                 snprintf(tz_name, sizeof(tz_name), "mlxsw-lc%d-module%d",
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  419 |                          module_tz->slot_index, module_tz->module + 1);
      |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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

Comments

Jakub Kicinski Aug. 1, 2024, 1:40 a.m. UTC | #1 
On Tue, 30 Jul 2024 15:58:21 +0200 Petr Machata wrote:
> From: Ido Schimmel <idosch@nvidia.com>
> 
> The name of a thermal zone device cannot be longer than 19 characters
> ('THERMAL_NAME_LENGTH - 1'). The format string 'mlxsw-lc%d-module%d' can
> exceed this limitation if the maximum number of line cards cannot be
> represented using a single digit and the maximum number of transceiver
> modules cannot be represented using two digits.

The ordering could have been better since this comes from patch 6 
in the same series :(
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
index 269c4986ea24..303d2ce4dc1e 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
@@ -411,7 +411,7 @@  static const struct thermal_cooling_device_ops mlxsw_cooling_ops = {
 static int
 mlxsw_thermal_module_tz_init(struct mlxsw_thermal_module *module_tz)
 {
-	char tz_name[THERMAL_NAME_LENGTH];
+	char tz_name[40];
 	int err;
 
 	if (module_tz->slot_index)