When build with W=1 and "-Werror=format-truncation", below error is
observed in coretemp driver,
drivers/hwmon/coretemp.c: In function 'create_core_data':
>> drivers/hwmon/coretemp.c:393:34: error: '%s' directive output may be truncated writing likely 5 or more bytes into a region of size between 3 and 13 [-Werror=format-truncation=]
393 | "temp%d_%s", attr_no, suffixes[i]);
| ^~
drivers/hwmon/coretemp.c:393:26: note: assuming directive output of 5 bytes
393 | "temp%d_%s", attr_no, suffixes[i]);
| ^~~~~~~~~~~
drivers/hwmon/coretemp.c:392:17: note: 'snprintf' output 7 or more bytes (assuming 22) into a destination of size 19
392 | snprintf(tdata->attr_name[i], CORETEMP_NAME_LENGTH,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
393 | "temp%d_%s", attr_no, suffixes[i]);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
Given that
1. '%d' could take 10 charactors,
2. '%s' could take 10 charactors ("crit_alarm"),
3. "temp", "_" and the NULL terminator take 6 charactors,
fix the problem by increasing CORETEMP_NAME_LENGTH to 28.
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Fixes: 7108b80a542b ("hwmon/coretemp: Handle large core ID value")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202310200443.iD3tUbbK-lkp@xxxxxxxxx/
---
Note that, in practice, I found that the problem is gone if I increase
the size to 22. But I cannot explain this.
---
drivers/hwmon/coretemp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index eba94f68585a..ba82d1e79c13 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -42,7 +42,7 @@ MODULE_PARM_DESC(tjmax, "TjMax value in degrees Celsius");
#define PKG_SYSFS_ATTR_NO 1 /* Sysfs attribute for package temp */
#define BASE_SYSFS_ATTR_NO 2 /* Sysfs Base attr no for coretemp */
#define NUM_REAL_CORES 128 /* Number of Real cores per cpu */
-#define CORETEMP_NAME_LENGTH 19 /* String Length of attrs */
+#define CORETEMP_NAME_LENGTH 28 /* String Length of attrs */
#define MAX_CORE_ATTRS 4 /* Maximum no of basic attrs */
#define TOTAL_ATTRS (MAX_CORE_ATTRS + 1)
#define MAX_CORE_DATA (NUM_REAL_CORES + BASE_SYSFS_ATTR_NO)
--
2.34.1
