Re: [PATCH v3 2/3] treewide: Switch memcpy() users of 'task->comm' to a more safer implementation

[kernel test robot <lkp@intel.com>]

Hi Bhupesh,

kernel test robot noticed the following build errors:

[auto build test ERROR on trace/for-next]
[also build test ERROR on tip/sched/core akpm-mm/mm-everything linus/master v6.15-rc5 next-20250508]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Bhupesh/exec-Remove-obsolete-comments/20250507-190740
base:   https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link:    https://lore.kernel.org/r/20250507110444.963779-3-bhupesh%40igalia.com
patch subject: [PATCH v3 2/3] treewide: Switch memcpy() users of 'task->comm' to a more safer implementation
config: x86_64-defconfig (https://download.01.org/0day-ci/archive/20250508/202505082038.A5ejhbR4-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250508/202505082038.A5ejhbR4-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505082038.A5ejhbR4-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/trace/define_trace.h:119,
                    from include/trace/events/sched.h:856,
                    from kernel/sched/core.c:84:
   include/trace/events/sched.h: In function 'do_trace_event_raw_event_sched_switch':
>> include/trace/events/sched.h:245:24: error: 'struct trace_event_raw_sched_switch' has no member named 'comm'
     245 |                 __entry->comm[TASK_COMM_LEN - 1] = '\0';
         |                        ^~
   include/trace/trace_events.h:427:11: note: in definition of macro '__DECLARE_EVENT_CLASS'
     427 |         { assign; }                                                     \
         |           ^~~~~~
   include/trace/trace_events.h:435:23: note: in expansion of macro 'PARAMS'
     435 |                       PARAMS(assign), PARAMS(print))                    \
         |                       ^~~~~~
   include/trace/trace_events.h:40:9: note: in expansion of macro 'DECLARE_EVENT_CLASS'
      40 |         DECLARE_EVENT_CLASS(name,                              \
         |         ^~~~~~~~~~~~~~~~~~~
   include/trace/trace_events.h:44:30: note: in expansion of macro 'PARAMS'
      44 |                              PARAMS(assign),                   \
         |                              ^~~~~~
   include/trace/events/sched.h:224:1: note: in expansion of macro 'TRACE_EVENT'
     224 | TRACE_EVENT(sched_switch,
         | ^~~~~~~~~~~
   include/trace/events/sched.h:243:9: note: in expansion of macro 'TP_fast_assign'
     243 |         TP_fast_assign(
         |         ^~~~~~~~~~~~~~
   In file included from include/trace/define_trace.h:120,
                    from include/trace/events/sched.h:856,
                    from kernel/sched/core.c:84:
   include/trace/events/sched.h: In function 'do_perf_trace_sched_switch':
>> include/trace/events/sched.h:245:24: error: 'struct trace_event_raw_sched_switch' has no member named 'comm'
     245 |                 __entry->comm[TASK_COMM_LEN - 1] = '\0';
         |                        ^~
   include/trace/perf.h:51:11: note: in definition of macro '__DECLARE_EVENT_CLASS'
      51 |         { assign; }                                                     \
         |           ^~~~~~
   include/trace/perf.h:67:23: note: in expansion of macro 'PARAMS'
      67 |                       PARAMS(assign), PARAMS(print))                    \
         |                       ^~~~~~
   include/trace/trace_events.h:40:9: note: in expansion of macro 'DECLARE_EVENT_CLASS'
      40 |         DECLARE_EVENT_CLASS(name,                              \
         |         ^~~~~~~~~~~~~~~~~~~
   include/trace/trace_events.h:44:30: note: in expansion of macro 'PARAMS'
      44 |                              PARAMS(assign),                   \
         |                              ^~~~~~
   include/trace/events/sched.h:224:1: note: in expansion of macro 'TRACE_EVENT'
     224 | TRACE_EVENT(sched_switch,
         | ^~~~~~~~~~~
   include/trace/events/sched.h:243:9: note: in expansion of macro 'TP_fast_assign'
     243 |         TP_fast_assign(
         |         ^~~~~~~~~~~~~~


vim +245 include/trace/events/sched.h

   225	
   226		TP_PROTO(bool preempt,
   227			 struct task_struct *prev,
   228			 struct task_struct *next,
   229			 unsigned int prev_state),
   230	
   231		TP_ARGS(preempt, prev, next, prev_state),
   232	
   233		TP_STRUCT__entry(
   234			__array(	char,	prev_comm,	TASK_COMM_LEN	)
   235			__field(	pid_t,	prev_pid			)
   236			__field(	int,	prev_prio			)
   237			__field(	long,	prev_state			)
   238			__array(	char,	next_comm,	TASK_COMM_LEN	)
   239			__field(	pid_t,	next_pid			)
   240			__field(	int,	next_prio			)
   241		),
   242	
   243		TP_fast_assign(
   244			memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
 > 245			__entry->comm[TASK_COMM_LEN - 1] = '\0';
   246			__entry->prev_pid	= prev->pid;
   247			__entry->prev_prio	= prev->prio;
   248			__entry->prev_state	= __trace_sched_switch_state(preempt, prev_state, prev);
   249			memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
   250			__entry->next_comm[TASK_COMM_LEN - 1] = '\0';
   251			__entry->next_pid	= next->pid;
   252			__entry->next_prio	= next->prio;
   253			/* XXX SCHED_DEADLINE */
   254		),
   255	
   256		TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==> next_comm=%s next_pid=%d next_prio=%d",
   257			__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
   258	
   259			(__entry->prev_state & (TASK_REPORT_MAX - 1)) ?
   260			  __print_flags(__entry->prev_state & (TASK_REPORT_MAX - 1), "|",
   261					{ TASK_INTERRUPTIBLE, "S" },
   262					{ TASK_UNINTERRUPTIBLE, "D" },
   263					{ __TASK_STOPPED, "T" },
   264					{ __TASK_TRACED, "t" },
   265					{ EXIT_DEAD, "X" },
   266					{ EXIT_ZOMBIE, "Z" },
   267					{ TASK_PARKED, "P" },
   268					{ TASK_DEAD, "I" }) :
   269			  "R",
   270	
   271			__entry->prev_state & TASK_REPORT_MAX ? "+" : "",
   272			__entry->next_comm, __entry->next_pid, __entry->next_prio)
   273	);
   274	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki