Re: drivers/leds/trigger/ledtrig-netdev.c:120:34: warning: array subscript 17 is above array bounds of 'char[16]'

[Liu, Yujie]

On Fri, 2023-09-29 at 12:26 +0200, Christian Marangi wrote:
> On Wed, Sep 27, 2023 at 10:44:22PM +0800, Philip Li wrote:
> > On Tue, Sep 26, 2023 at 01:22:35AM +0200, Christian Marangi wrote:
> > > On Tue, Sep 19, 2023 at 08:21:03PM +0800, kernel test robot
> > > wrote:
> > > > tree:  
> > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > > >  master
> > > > head:   2cf0f715623872823a72e451243bbf555d10d032
> > > > commit: 28a6a2ef18ad840a390d519840c303b03040961c leds: trigger:
> > > > netdev: refactor code setting device name
> > > > date:   4 months ago
> > > > config: loongarch-allmodconfig
> > > > (https://download.01.org/0day-ci/archive/20230919/202309192035
> > > > .GTJEEbem-lkp@xxxxxxxxx/config)
> > > > compiler: loongarch64-linux-gcc (GCC) 13.2.0
> > > > reproduce (this is a W=1 build):
> > > > (https://download.01.org/0day-ci/archive/20230919/202309192035
> > > > .GTJEEbem-lkp@xxxxxxxxx/reproduce)
> > > > 
> > > > If you fix the issue in a separate patch/commit (i.e. not just
> > > > a new version of
> > > > the same patch/commit), kindly add following tags
> > > > > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > > > > Closes:
> > > > > https://lore.kernel.org/oe-kbuild-all/202309192035.GTJEEbem-lkp@xxxxxxxxx/
> > > > 
> > > > All warnings (new ones prefixed by >>):
> > > > 
> > > >    drivers/leds/trigger/ledtrig-netdev.c: In function
> > > > 'set_device_name':
> > > > > > drivers/leds/trigger/ledtrig-netdev.c:120:34: warning:
> > > > > > array subscript 17 is above array bounds of 'char[16]' [-
> > > > > > Warray-bounds=]
> > > >      120 |         trigger_data->device_name[size] = 0;
> > > >          |         ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> > > >    drivers/leds/trigger/ledtrig-netdev.c:48:14: note: while
> > > > referencing 'device_name'
> > > >       48 |         char device_name[IFNAMSIZ];
> > > >          |              ^~~~~~~~~~~
> > > > > > drivers/leds/trigger/ledtrig-netdev.c:120:34: warning:
> > > > > > array subscript 17 is above array bounds of 'char[16]' [-
> > > > > > Warray-bounds=]
> > > >      120 |         trigger_data->device_name[size] = 0;
> > > >          |         ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> > > >    drivers/leds/trigger/ledtrig-netdev.c:48:14: note: while
> > > > referencing 'device_name'
> > > >       48 |         char device_name[IFNAMSIZ];
> > > >          |              ^~~~~~~~~~~
> > > > 
> > > > 
> > > > vim +120 drivers/leds/trigger/ledtrig-netdev.c
> > > > 
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  106  
> > > > 28a6a2ef18ad84 Andrew Lunn       2023-05-29  107  static int
> > > > set_device_name(struct led_netdev_data *trigger_data,
> > > > 28a6a2ef18ad84 Andrew Lunn       2023-05-29 
> > > > 108                           const char *name, size_t size)
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  109  {
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 110        cancel_delayed_work_sync(&trigger_data->work);
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  111  
> > > > d1b9e1391ab2dc Christian Marangi 2023-04-19 
> > > > 112        mutex_lock(&trigger_data->lock);
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  113  
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  114        if
> > > > (trigger_data->net_dev) {
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 115                dev_put(trigger_data->net_dev);
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 116                trigger_data->net_dev = NULL;
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  117        }
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  118  
> > > > 28a6a2ef18ad84 Andrew Lunn       2023-05-29 
> > > > 119        memcpy(trigger_data->device_name, name, size);
> > > > 909346433064b8 Rasmus Villemoes  2019-03-14
> > > > @120        trigger_data->device_name[size] = 0;
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  121        if
> > > > (size > 0 && trigger_data->device_name[size - 1] == '\n')
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 122                trigger_data->device_name[size - 1] = 0;
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  123  
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  124        if
> > > > (trigger_data->device_name[0] != 0)
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 125                trigger_data->net_dev =
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 126                    dev_get_by_name(&init_net, trigger_data-
> > > > >device_name);
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  127  
> > > > e2f24cb1b5daf9 Christian Marangi 2023-04-19 
> > > > 128        trigger_data->carrier_link_up = false;
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  129        if
> > > > (trigger_data->net_dev != NULL)
> > > > e2f24cb1b5daf9 Christian Marangi 2023-04-19 
> > > > 130                trigger_data->carrier_link_up =
> > > > netif_carrier_ok(trigger_data->net_dev);
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  131  
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 132        trigger_data->last_activity = 0;
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  133  
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10 
> > > > 134        set_baseline_state(trigger_data);
> > > > d1b9e1391ab2dc Christian Marangi 2023-04-19 
> > > > 135        mutex_unlock(&trigger_data->lock);
> > > > 06f502f57d0d77 Ben Whitten       2017-12-10  136  
> > > > 28a6a2ef18ad84 Andrew Lunn       2023-05-29  137        return
> > > > 0;
> > > > 28a6a2ef18ad84 Andrew Lunn       2023-05-29  138  }
> > > > 28a6a2ef18ad84 Andrew Lunn       2023-05-29  139  
> > > > 
> > > > :::::: The code at line 120 was first introduced by commit
> > > > :::::: 909346433064b8d840dc82af26161926b8d37558 leds: trigger:
> > > > netdev: use memcpy in device_name_store
> > > > 
> > > > :::::: TO: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> > > > :::::: CC: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>
> > > > 
> > > > -- 
> > > > 0-DAY CI Kernel Test Service
> > > > https://github.com/intel/lkp-tests/wiki
> > > 
> > > Can't repro so I guess this was a false-positive that got fixed?
> > > (I used
> > > the repro commands and doesn't print any error)
> > 
> > Hi Ansuel, the issue requires to build with -Warray-bounds flag. We
> > will fix
> > the reproduce steps in earliest time. Sorry for the inconvenience.
> > 
> 
> Hi again, happy to help you further.
> 
> By adding the flag I still can't repro.
> I'm using this command.
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/bin/make.cross
> W=1 O=build_dir ARCH=loongarch SHELL=/bin/bash drivers/leds/trigger/ 
> -Warray-bounds

Hi Ansuel, we added some extra compiler flags recently but the repro
steps were not updated in time. Sorry for this.

Could you please have a try with the following command? (append
KCFLAGS="-Warray-bounds" at the end)

COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-13.2.0 ~/bin/make.cross W=1 O=build_dir ARCH=loongarch SHELL=/bin/bash drivers/leds/trigger/ KCFLAGS="-Warray-bounds"

> Also on top of that I can see that only ledtrig-audio is compiled.
> From what I can see using olddefconfig won't actually use the config
> used by the bot.

The original config used by the bot can be obtained by:

$ wget
https://download.01.org/0day-ci/archive/20230919/202309192035.GTJEEbem-lkp@xxxxxxxxx/config
-O build_dir/.config

"make olddefconfig" is for refreshing it to resolve potential config
dependencies.

> By manually adding the config of the bot to the build_dir ledtrig-
> netdev
> is correctly compiled and still no warning about this.
> 
> I'm here to any test needed to improve the repro instructions.
>