[openeuler:openEuler-1.0-LTS 1334/1334] kernel/hung_task.c:148:7: error: use of undeclared identifier 'sysctl_hung_task_all_cpu_backtrace'

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

Hi Guilherme,

FYI, the error/warning still remains.

tree:   https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS
head:   33c097cb0d6c8c1dcf8cde0f66b1c6c907ee2740
commit: 190aae97bcddbed131a203f829257b168f5058ce [1334/1334] kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected
config: x86_64-randconfig-103-20241218 (https://download.01.org/0day-ci/archive/20250227/202502271605.5iiFNfaf-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250227/202502271605.5iiFNfaf-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/202502271605.5iiFNfaf-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/hung_task.c:148:7: error: use of undeclared identifier 'sysctl_hung_task_all_cpu_backtrace'
     148 |                 if (sysctl_hung_task_all_cpu_backtrace)
         |                     ^
   kernel/hung_task.c:235:5: warning: no previous prototype for function 'proc_dohung_task_timeout_secs' [-Wmissing-prototypes]
     235 | int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
         |     ^
   kernel/hung_task.c:235:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     235 | int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
         | ^
         | static 
   1 warning and 1 error generated.


vim +/sysctl_hung_task_all_cpu_backtrace +148 kernel/hung_task.c

    94	
    95	static void check_hung_task(struct task_struct *t, unsigned long timeout)
    96	{
    97		unsigned long switch_count = t->nvcsw + t->nivcsw;
    98	
    99		/*
   100		 * Ensure the task is not frozen.
   101		 * Also, skip vfork and any other user process that freezer should skip.
   102		 */
   103		if (unlikely(t->flags & (PF_FROZEN | PF_FREEZER_SKIP)))
   104		    return;
   105	
   106		/*
   107		 * When a freshly created task is scheduled once, changes its state to
   108		 * TASK_UNINTERRUPTIBLE without having ever been switched out once, it
   109		 * musn't be checked.
   110		 */
   111		if (unlikely(!switch_count))
   112			return;
   113	
   114		if (switch_count != t->last_switch_count) {
   115			t->last_switch_count = switch_count;
   116			t->last_switch_time = jiffies;
   117			return;
   118		}
   119		if (time_is_after_jiffies(t->last_switch_time + timeout * HZ))
   120			return;
   121	
   122		trace_sched_process_hang(t);
   123	
   124		if (sysctl_hung_task_panic) {
   125			console_verbose();
   126			hung_task_show_lock = true;
   127			hung_task_call_panic = true;
   128		}
   129	
   130		/*
   131		 * Ok, the task did not get scheduled for more than 2 minutes,
   132		 * complain:
   133		 */
   134		if (sysctl_hung_task_warnings) {
   135			if (sysctl_hung_task_warnings > 0)
   136				sysctl_hung_task_warnings--;
   137			pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
   138				t->comm, t->pid, timeout);
   139			pr_err("      %s %s %.*s\n",
   140				print_tainted(), init_utsname()->release,
   141				(int)strcspn(init_utsname()->version, " "),
   142				init_utsname()->version);
   143			pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
   144				" disables this message.\n");
   145			sched_show_task(t);
   146			hung_task_show_lock = true;
   147	
 > 148			if (sysctl_hung_task_all_cpu_backtrace)
   149				hung_task_show_all_bt = true;
   150		}
   151	
   152		touch_nmi_watchdog();
   153	}
   154	

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