[PATCH net-next] sfc: avoid truncating MCDI hwmon attribute names

[PATCH net-next] sfc: avoid truncating MCDI hwmon attribute names

[xujiahao]

The name of each MCDI hwmon attribute is built in a 12-byte buffer as
prefix + 1-based per-type index + suffix, with prefixes up to "power"
and suffixes up to "_input".  With W=1 gcc reports:

  warning: 'snprintf' output may be truncated before the last format
  character [-Wformat-truncation=]

at mcdi_mon.c:457, :488 and :495, in both the sfc and the siena copy.

The same 12-byte field in struct efx_mcdi_mon_attribute, which receives
a strscpy() of the local buffer and backs the sysfs attribute name,
would also truncate silently once a sensor type has more than 9
instances: "power10_crit" already needs 13 bytes.

Enlarge both buffers to 24 bytes, enough for the longest possible name:
"power" + 10 digits + "_input" + NUL = 22 bytes.

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/all/202401100509.U4prhh6J-lkp@intel.com/
Signed-off-by: xujiahao <xujiahao@cmss.chinamobile.com>
---
 drivers/net/ethernet/sfc/mcdi_mon.c       | 4 ++--
 drivers/net/ethernet/sfc/siena/mcdi_mon.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/sfc/mcdi_mon.c b/drivers/net/ethernet/sfc/mcdi_mon.c
index e574f91f6..9700228df 100644
--- a/drivers/net/ethernet/sfc/mcdi_mon.c
+++ b/drivers/net/ethernet/sfc/mcdi_mon.c
@@ -138,7 +138,7 @@ struct efx_mcdi_mon_attribute {
 	unsigned int type;
 	enum efx_hwmon_type hwmon_type;
 	unsigned int limit_value;
-	char name[12];
+	char name[24];
 };
 
 static int efx_mcdi_mon_update(struct efx_nic *efx)
@@ -308,7 +308,7 @@ int efx_mcdi_mon_probe(struct efx_nic *efx)
 	MCDI_DECLARE_BUF(outbuf, MC_CMD_SENSOR_INFO_OUT_LENMAX);
 	unsigned int n_pages, n_sensors, n_attrs, page;
 	size_t outlen;
-	char name[12];
+	char name[24];
 	u32 mask;
 	int rc, i, j, type;
 
diff --git a/drivers/net/ethernet/sfc/siena/mcdi_mon.c b/drivers/net/ethernet/sfc/siena/mcdi_mon.c
index 0216a2a60..0037f603f 100644
--- a/drivers/net/ethernet/sfc/siena/mcdi_mon.c
+++ b/drivers/net/ethernet/sfc/siena/mcdi_mon.c
@@ -138,7 +138,7 @@ struct efx_mcdi_mon_attribute {
 	unsigned int type;
 	enum efx_hwmon_type hwmon_type;
 	unsigned int limit_value;
-	char name[12];
+	char name[24];
 };
 
 static int efx_mcdi_mon_update(struct efx_nic *efx)
@@ -308,7 +308,7 @@ int efx_siena_mcdi_mon_probe(struct efx_nic *efx)
 	MCDI_DECLARE_BUF(outbuf, MC_CMD_SENSOR_INFO_OUT_LENMAX);
 	unsigned int n_pages, n_sensors, n_attrs, page;
 	size_t outlen;
-	char name[12];
+	char name[24];
 	u32 mask;
 	int rc, i, j, type;
 
-- 
2.43.0

Re: [PATCH net-next] sfc: avoid truncating MCDI hwmon attribute names

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu,  5 Nov 2026 10:01:15 +0800 you wrote:
> The name of each MCDI hwmon attribute is built in a 12-byte buffer as
> prefix + 1-based per-type index + suffix, with prefixes up to "power"
> and suffixes up to "_input".  With W=1 gcc reports:
> 
>   warning: 'snprintf' output may be truncated before the last format
>   character [-Wformat-truncation=]
> 
> [...]

Here is the summary with links:
  - [net-next] sfc: avoid truncating MCDI hwmon attribute names
    https://git.kernel.org/netdev/net-next/c/97ced2c090bf

You are awesome, thank you!
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