tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: d96cd567c8d8d584405abe92c2576bf58202fa6e commit: 190aae97bcddbed131a203f829257b168f5058ce [1605/1605] kernel/hung_task.c: introduce sysctl to print all traces when a hung task is detected config: x86_64-buildonly-randconfig-2002-20250501 (https://download.01.org/0day-ci/archive/20250702/202507021631.OYJPyxwP-lkp@i...) compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250702/202507021631.OYJPyxwP-lkp@i...) 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/202507021631.OYJPyxwP-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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