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* kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute
@ 2021-06-04 11:12 kernel test robot
  2021-06-04 20:48 ` Steven Rostedt
  0 siblings, 1 reply; 3+ messages in thread
From: kernel test robot @ 2021-06-04 11:12 UTC (permalink / raw)
  To: Steven Rostedt (VMware); +Cc: kbuild-all, linux-kernel

[-- Attachment #1: Type: text/plain, Size: 2658 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   f88cd3fb9df228e5ce4e13ec3dbad671ddb2146e
commit: 9a6944fee68e25084130386c608c5ac8db487581 tracing: Add a verifier to check string pointers for trace events
date:   3 months ago
config: x86_64-rhel (attached as .config)
compiler: gcc-6 (Ubuntu 6.4.0-17ubuntu1) 6.4.0 20180424
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9a6944fee68e25084130386c608c5ac8db487581
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 9a6944fee68e25084130386c608c5ac8db487581
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   kernel/trace/trace.c: In function 'test_can_verify_check':
>> kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
     vsnprintf(buf, 16, "%d", ap);
     ^~~~~~~~~
   kernel/trace/trace.c: In function 'trace_check_vprintf':
   kernel/trace/trace.c:3717:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
      trace_seq_vprintf(&iter->seq, iter->fmt, ap);
      ^~~~~~~~~~~~~~~~~
   kernel/trace/trace.c:3756:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
      trace_seq_vprintf(&iter->seq, p, ap);
      ^~~~~~~~~~~~~~~~~


vim +/gnu_printf +3634 kernel/trace/trace.c

  3617	
  3618	static int test_can_verify_check(const char *fmt, ...)
  3619	{
  3620		char buf[16];
  3621		va_list ap;
  3622		int ret;
  3623	
  3624		/*
  3625		 * The verifier is dependent on vsnprintf() modifies the va_list
  3626		 * passed to it, where it is sent as a reference. Some architectures
  3627		 * (like x86_32) passes it by value, which means that vsnprintf()
  3628		 * does not modify the va_list passed to it, and the verifier
  3629		 * would then need to be able to understand all the values that
  3630		 * vsnprintf can use. If it is passed by value, then the verifier
  3631		 * is disabled.
  3632		 */
  3633		va_start(ap, fmt);
> 3634		vsnprintf(buf, 16, "%d", ap);
  3635		ret = va_arg(ap, int);
  3636		va_end(ap);
  3637	
  3638		return ret;
  3639	}
  3640	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute
  2021-06-04 11:12 kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute kernel test robot
@ 2021-06-04 20:48 ` Steven Rostedt
  2021-06-07  5:49   ` [kbuild-all] " Rong Chen
  0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2021-06-04 20:48 UTC (permalink / raw)
  To: kernel test robot; +Cc: kbuild-all, linux-kernel

On Fri, 4 Jun 2021 19:12:03 +0800
kernel test robot <lkp@intel.com> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   f88cd3fb9df228e5ce4e13ec3dbad671ddb2146e
> commit: 9a6944fee68e25084130386c608c5ac8db487581 tracing: Add a verifier to check string pointers for trace events
> date:   3 months ago
> config: x86_64-rhel (attached as .config)
> compiler: gcc-6 (Ubuntu 6.4.0-17ubuntu1) 6.4.0 20180424
> reproduce (this is a W=1 build):
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9a6944fee68e25084130386c608c5ac8db487581
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout 9a6944fee68e25084130386c608c5ac8db487581
>         # save the attached .config to linux build tree
>         make W=1 ARCH=x86_64 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>    kernel/trace/trace.c: In function 'test_can_verify_check':
> >> kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]  
>      vsnprintf(buf, 16, "%d", ap);
>      ^~~~~~~~~

"test_can_verify_check" is not a generic function that needs a printf
format check. This is a bogus warning. Please remove it as being an issue.

-- Steve



>    kernel/trace/trace.c: In function 'trace_check_vprintf':
>    kernel/trace/trace.c:3717:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
>       trace_seq_vprintf(&iter->seq, iter->fmt, ap);
>       ^~~~~~~~~~~~~~~~~
>    kernel/trace/trace.c:3756:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
>       trace_seq_vprintf(&iter->seq, p, ap);
>       ^~~~~~~~~~~~~~~~~
> 
> 
> vim +/gnu_printf +3634 kernel/trace/trace.c
> 
>   3617	
>   3618	static int test_can_verify_check(const char *fmt, ...)
>   3619	{
>   3620		char buf[16];
>   3621		va_list ap;
>   3622		int ret;
>   3623	
>   3624		/*
>   3625		 * The verifier is dependent on vsnprintf() modifies the va_list
>   3626		 * passed to it, where it is sent as a reference. Some architectures
>   3627		 * (like x86_32) passes it by value, which means that vsnprintf()
>   3628		 * does not modify the va_list passed to it, and the verifier
>   3629		 * would then need to be able to understand all the values that
>   3630		 * vsnprintf can use. If it is passed by value, then the verifier
>   3631		 * is disabled.
>   3632		 */
>   3633		va_start(ap, fmt);
> > 3634		vsnprintf(buf, 16, "%d", ap);  
>   3635		ret = va_arg(ap, int);
>   3636		va_end(ap);
>   3637	
>   3638		return ret;
>   3639	}
>   3640	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org


^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [kbuild-all] Re: kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute
  2021-06-04 20:48 ` Steven Rostedt
@ 2021-06-07  5:49   ` Rong Chen
  0 siblings, 0 replies; 3+ messages in thread
From: Rong Chen @ 2021-06-07  5:49 UTC (permalink / raw)
  To: Steven Rostedt, kernel test robot; +Cc: kbuild-all, linux-kernel



On 6/5/21 4:48 AM, Steven Rostedt wrote:
> On Fri, 4 Jun 2021 19:12:03 +0800
> kernel test robot <lkp@intel.com> wrote:
>
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   f88cd3fb9df228e5ce4e13ec3dbad671ddb2146e
>> commit: 9a6944fee68e25084130386c608c5ac8db487581 tracing: Add a verifier to check string pointers for trace events
>> date:   3 months ago
>> config: x86_64-rhel (attached as .config)
>> compiler: gcc-6 (Ubuntu 6.4.0-17ubuntu1) 6.4.0 20180424
>> reproduce (this is a W=1 build):
>>          # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9a6944fee68e25084130386c608c5ac8db487581
>>          git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>          git fetch --no-tags linus master
>>          git checkout 9a6944fee68e25084130386c608c5ac8db487581
>>          # save the attached .config to linux build tree
>>          make W=1 ARCH=x86_64
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>>
>> All warnings (new ones prefixed by >>):
>>
>>     kernel/trace/trace.c: In function 'test_can_verify_check':
>>>> kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
>>       vsnprintf(buf, 16, "%d", ap);
>>       ^~~~~~~~~
> "test_can_verify_check" is not a generic function that needs a printf
> format check. This is a bogus warning. Please remove it as being an issue.
>
> -- Steve
>

Hi Steve,

Thanks for the feedback, we'll ignore the commit to avoid new reports 
for this warning.

Best Regards,
Rong Chen

>
>>     kernel/trace/trace.c: In function 'trace_check_vprintf':
>>     kernel/trace/trace.c:3717:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
>>        trace_seq_vprintf(&iter->seq, iter->fmt, ap);
>>        ^~~~~~~~~~~~~~~~~
>>     kernel/trace/trace.c:3756:3: warning: function might be possible candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
>>        trace_seq_vprintf(&iter->seq, p, ap);
>>        ^~~~~~~~~~~~~~~~~
>>
>>
>> vim +/gnu_printf +3634 kernel/trace/trace.c
>>
>>    3617	
>>    3618	static int test_can_verify_check(const char *fmt, ...)
>>    3619	{
>>    3620		char buf[16];
>>    3621		va_list ap;
>>    3622		int ret;
>>    3623	
>>    3624		/*
>>    3625		 * The verifier is dependent on vsnprintf() modifies the va_list
>>    3626		 * passed to it, where it is sent as a reference. Some architectures
>>    3627		 * (like x86_32) passes it by value, which means that vsnprintf()
>>    3628		 * does not modify the va_list passed to it, and the verifier
>>    3629		 * would then need to be able to understand all the values that
>>    3630		 * vsnprintf can use. If it is passed by value, then the verifier
>>    3631		 * is disabled.
>>    3632		 */
>>    3633		va_start(ap, fmt);
>>> 3634		vsnprintf(buf, 16, "%d", ap);
>>    3635		ret = va_arg(ap, int);
>>    3636		va_end(ap);
>>    3637	
>>    3638		return ret;
>>    3639	}
>>    3640	
>>
>> ---
>> 0-DAY CI Kernel Test Service, Intel Corporation
>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> _______________________________________________
> kbuild-all mailing list -- kbuild-all@lists.01.org
> To unsubscribe send an email to kbuild-all-leave@lists.01.org


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2021-06-04 11:12 kernel/trace/trace.c:3634:2: warning: function might be possible candidate for 'gnu_printf' format attribute kernel test robot
2021-06-04 20:48 ` Steven Rostedt
2021-06-07  5:49   ` [kbuild-all] " Rong Chen

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