1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/sched/debug.h> 3 #include <linux/console.h> 4 #include <linux/kernel.h> 5 #include <linux/ftrace.h> 6 #include <linux/sysctl.h> 7 #include <linux/nmi.h> 8 9 #include <linux/sys_info.h> 10 11 struct sys_info_name { 12 unsigned long bit; 13 const char *name; 14 }; 15 16 /* 17 * When 'si_names' gets updated, please make sure the 'sys_info_avail' 18 * below is updated accordingly. 19 */ 20 static const struct sys_info_name si_names[] = { 21 { SYS_INFO_TASKS, "tasks" }, 22 { SYS_INFO_MEM, "mem" }, 23 { SYS_INFO_TIMERS, "timers" }, 24 { SYS_INFO_LOCKS, "locks" }, 25 { SYS_INFO_FTRACE, "ftrace" }, 26 { SYS_INFO_ALL_CPU_BT, "all_bt" }, 27 { SYS_INFO_BLOCKED_TASKS, "blocked_tasks" }, 28 }; 29 30 /* Expecting string like "xxx_sys_info=tasks,mem,timers,locks,ftrace,..." */ 31 unsigned long sys_info_parse_param(char *str) 32 { 33 unsigned long si_bits = 0; 34 char *s, *name; 35 int i; 36 37 s = str; 38 while ((name = strsep(&s, ",")) && *name) { 39 for (i = 0; i < ARRAY_SIZE(si_names); i++) { 40 if (!strcmp(name, si_names[i].name)) { 41 si_bits |= si_names[i].bit; 42 break; 43 } 44 } 45 } 46 47 return si_bits; 48 } 49 50 #ifdef CONFIG_SYSCTL 51 52 static const char sys_info_avail[] __maybe_unused = "tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks"; 53 54 int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write, 55 void *buffer, size_t *lenp, 56 loff_t *ppos) 57 { 58 char names[sizeof(sys_info_avail) + 1]; 59 struct ctl_table table; 60 unsigned long *si_bits_global; 61 62 si_bits_global = ro_table->data; 63 64 if (write) { 65 unsigned long si_bits; 66 int ret; 67 68 table = *ro_table; 69 table.data = names; 70 table.maxlen = sizeof(names); 71 ret = proc_dostring(&table, write, buffer, lenp, ppos); 72 if (ret) 73 return ret; 74 75 si_bits = sys_info_parse_param(names); 76 /* The access to the global value is not synchronized. */ 77 WRITE_ONCE(*si_bits_global, si_bits); 78 return 0; 79 } else { 80 /* for 'read' operation */ 81 char *delim = ""; 82 int i, len = 0; 83 84 for (i = 0; i < ARRAY_SIZE(si_names); i++) { 85 if (*si_bits_global & si_names[i].bit) { 86 len += scnprintf(names + len, sizeof(names) - len, 87 "%s%s", delim, si_names[i].name); 88 delim = ","; 89 } 90 } 91 92 table = *ro_table; 93 table.data = names; 94 table.maxlen = sizeof(names); 95 return proc_dostring(&table, write, buffer, lenp, ppos); 96 } 97 } 98 #endif 99 100 void sys_info(unsigned long si_mask) 101 { 102 if (si_mask & SYS_INFO_TASKS) 103 show_state(); 104 105 if (si_mask & SYS_INFO_MEM) 106 show_mem(); 107 108 if (si_mask & SYS_INFO_TIMERS) 109 sysrq_timer_list_show(); 110 111 if (si_mask & SYS_INFO_LOCKS) 112 debug_show_all_locks(); 113 114 if (si_mask & SYS_INFO_FTRACE) 115 ftrace_dump(DUMP_ALL); 116 117 if (si_mask & SYS_INFO_ALL_CPU_BT) 118 trigger_all_cpu_backtrace(); 119 120 if (si_mask & SYS_INFO_BLOCKED_TASKS) 121 show_state_filter(TASK_UNINTERRUPTIBLE); 122 } 123