platform/x86: peaq-wmi: select INPUT_POLLDEV

gcc points out a possible format string overflow for a large value of 'zone':

drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init':
drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=]

   sprintf(buffer, "zone%02X", i);
                        ^~~~
drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646]
   sprintf(buffer, "zone%02X", i);
                   ^~~~~~~~~~

drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10

This replaces the 'int' variable with an 'u8' to make sure it always fits, renaming the variable to 'zone' for clarity.

Unfortunately, gcc-7.1.1 still warns about it with that change, which seems to be unintended by the gcc developers. I have opened a bug against gcc with a reduced test case. As a workaround, I also change the format string to use "%02hhX", which shuts up the warning in that version.

Link https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81483

Link https://patchwork.ozlabs.org/patch/788415/

Suggested-by Andy Shevchenko <[email protected]>

Signed-off-by Arnd Bergmann <[email protected]>

---
v2: completely rewrite the patch after discussing with Andy

---
 drivers/platform/x86/alienware-wmi.c | 38 ++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

drivers/platform/x86/alienware-wmi.c +19 -20

index 0831b428c217..c56a9ecba959 100644
@@ -255,12 +255,12 @@ static int parse_rgb(const char *buf, struct platform_zone *zone)
 
 static struct platform_zone *match_zone(struct device_attribute *attr)
 {
-       int i;
-       for (i = 0; i < quirks->num_zones; i++) {
-               if ((struct device_attribute *)zone_data[i].attr == attr) {
+       u8 zone;
+       for (zone = 0; zone < quirks->num_zones; zone++) {
+               if ((struct device_attribute *)zone_data[zone].attr == attr) {
                        pr_debug("alienware-wmi: matched zone location: %d\n",
-                                zone_data[i].location);
-                       return &zone_data[i];
+                                zone_data[zone].location);
+                       return &zone_data[zone];
                }
        }
        return NULL;

@@ -420,7 +420,7 @@ static DEVICE_ATTR(lighting_control_state, 0644, show_control_state,
 
 static int alienware_zone_init(struct platform_device *dev)
 {
-       int i;
+       u8 zone;
        char buffer[10];
        char *name;
 

@@ -457,19 +457,19 @@ static int alienware_zone_init(struct platform_device *dev)
        if (!zone_data)
                return -ENOMEM;
 
-       for (i = 0; i < quirks->num_zones; i++) {
-               sprintf(buffer, "zone%02X", i);
+       for (zone = 0; zone < quirks->num_zones; zone++) {
+               sprintf(buffer, "zone%02hhX", zone);
                name = kstrdup(buffer, GFP_KERNEL);
                if (name == NULL)
                        return 1;
-               sysfs_attr_init(&zone_dev_attrs[i].attr);
-               zone_dev_attrs[i].attr.name = name;
-               zone_dev_attrs[i].attr.mode = 0644;
-               zone_dev_attrs[i].show = zone_show;
-               zone_dev_attrs[i].store = zone_set;
-               zone_data[i].location = i;
-               zone_attrs[i] = &zone_dev_attrs[i].attr;
-               zone_data[i].attr = &zone_dev_attrs[i];
+               sysfs_attr_init(&zone_dev_attrs[zone].attr);
+               zone_dev_attrs[zone].attr.name = name;
+               zone_dev_attrs[zone].attr.mode = 0644;
+               zone_dev_attrs[zone].show = zone_show;
+               zone_dev_attrs[zone].store = zone_set;
+               zone_data[zone].location = zone;
+               zone_attrs[zone] = &zone_dev_attrs[zone].attr;
+               zone_data[zone].attr = &zone_dev_attrs[zone];
        }
        zone_attrs[quirks->num_zones] = &dev_attr_lighting_control_state.attr;
        zone_attribute_group.attrs = zone_attrs;

@@ -484,9 +484,9 @@ static void alienware_zone_exit(struct platform_device *dev)
        sysfs_remove_group(&dev->dev.kobj, &zone_attribute_group);
        led_classdev_unregister(&global_led);
        if (zone_dev_attrs) {
-               int i;
-               for (i = 0; i < quirks->num_zones; i++)
-                       kfree(zone_dev_attrs[i].attr.name);
+               u8 zone;
+               for (zone = 0; zone < quirks->num_zones; zone++)
+                       kfree(zone_dev_attrs[zone].attr.name);
        }
        kfree(zone_dev_attrs);
        kfree(zone_data);
--

2.9.0

Quoted 11 lines · Arnd Bergmann

gcc points out a possible format string overflow for a large value of 'zone':

drivers/platform/x86/alienware-wmi.c: In function 'alienware_wmi_init':
drivers/platform/x86/alienware-wmi.c:461:24: error: '%02X' directive writing between 2 and 8 bytes into a region of size 6 [-Werror=format-overflow=]

   sprintf(buffer, "zone%02X", i);
                        ^~~~
drivers/platform/x86/alienware-wmi.c:461:19: note: directive argument in the range [0, 2147483646]
   sprintf(buffer, "zone%02X", i);
                   ^~~~~~~~~~

drivers/platform/x86/alienware-wmi.c:461:3: note: 'sprintf' output between 7 and 13 bytes into a destination of size 10

Quoted 9 lines

This replaces the 'int' variable with an 'u8' to make sure it always fits, renaming the variable to 'zone' for clarity.

Unfortunately, gcc-7.1.1 still warns about it with that change, which seems to be unintended by the gcc developers. I have opened a bug against gcc with a reduced test case. As a workaround, I also change the format string to use "%02hhX", which shuts up the warning in that version.

Thanks, pushed to testing with slight change (+ empty lines after u8 zone; where it's applicable).
I'm not going to move this to fixes queue since it looks to me not critical at all. Drop me a message if you think otherwise.

The new driver fails to build without INPUT_POLLDEV

drivers/platform/x86/peaq-wmi.o: In function `peaq_wmi_exit':
peaq-wmi.c:(.exit.text+0x1c): undefined reference to input_unregister_polled_device' drivers/platform/x86/peaq-wmi.o: In function peaq_wmi_init':
peaq-wmi.c:(.init.text+0x23): undefined reference to input_allocate_polled_device' peaq-wmi.c:(.init.text+0x18e): undefined reference to input_register_polled_device'

For some reason, all other drivers that need this use 'select' here rather than 'depends on', so I'm doing the same.

Fixes 13bb0fd5519d ("platform/x86: peaq-wmi: Add new peaq-wmi driver")

Signed-off-by Arnd Bergmann <[email protected]>