Re: [PATCH] tracing: Replace strncpy() with strscpy() when copying comm

[Jinjie Ruan]

On 2024/10/31 7:40, Steven Rostedt wrote:
> On Wed, 31 Jul 2024 15:50:58 +0800
> Jinjie Ruan <ruanjinjie@xxxxxxxxxx> wrote:
> 
>> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
>> index 6ece1308d36a..4ee0e64719fa 100644
>> --- a/kernel/trace/trace_events_hist.c
>> +++ b/kernel/trace/trace_events_hist.c
>> @@ -1599,7 +1599,7 @@ static inline void save_comm(char *comm, struct task_struct *task)
>>  		return;
>>  	}
>>  
>> -	strncpy(comm, task->comm, TASK_COMM_LEN);
>> +	strscpy(comm, task->comm);
>>  }
>>  
> 
> Was this even compiled?

Sorry, the trace_events_hist.c was left out, will fix it.

> 
> In file included from /work/git/test-linux.git/include/linux/container_of.h:5,
>                  from /work/git/test-linux.git/include/linux/list.h:5,
>                  from /work/git/test-linux.git/include/linux/module.h:12,
>                  from /work/git/test-linux.git/kernel/trace/trace_events_hist.c:8:
> /work/git/test-linux.git/kernel/trace/trace_events_hist.c: In function ‘save_comm’:
> /work/git/test-linux.git/include/linux/build_bug.h:16:51: error: negative width in bit-field ‘<anonymous>’
>    16 | #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
>       |                                                   ^
> /work/git/test-linux.git/include/linux/compiler.h:243:33: note: in expansion of macro ‘BUILD_BUG_ON_ZERO’
>   243 | #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
>       |                                 ^~~~~~~~~~~~~~~~~
> /work/git/test-linux.git/include/linux/string.h:79:47: note: in expansion of macro ‘__must_be_array’
>    79 |         sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst) +    \
>       |                                               ^~~~~~~~~~~~~~~
> /work/git/test-linux.git/include/linux/args.h:25:24: note: in expansion of macro ‘__strscpy0’
>    25 | #define __CONCAT(a, b) a ## b
>       |                        ^
> /work/git/test-linux.git/include/linux/args.h:26:27: note: in expansion of macro ‘__CONCAT’
>    26 | #define CONCATENATE(a, b) __CONCAT(a, b)
>       |                           ^~~~~~~~
> /work/git/test-linux.git/include/linux/string.h:113:9: note: in expansion of macro ‘CONCATENATE’
>   113 |         CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
>       |         ^~~~~~~~~~~
> /work/git/test-linux.git/kernel/trace/trace_events_hist.c:1602:9: note: in expansion of macro ‘strscpy’
>  1602 |         strscpy(comm, task->comm);
>       |         ^~~~~~~
> 
> Bah!
> 
> -- Steve
>