diff options
Diffstat (limited to 'lib/sys_info.c')
| -rw-r--r-- | lib/sys_info.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/lib/sys_info.c b/lib/sys_info.c new file mode 100644 index 000000000000..f32a06ec9ed4 --- /dev/null +++ b/lib/sys_info.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/array_size.h> +#include <linux/bitops.h> +#include <linux/cleanup.h> +#include <linux/console.h> +#include <linux/log2.h> +#include <linux/kernel.h> +#include <linux/ftrace.h> +#include <linux/nmi.h> +#include <linux/sched/debug.h> +#include <linux/string.h> +#include <linux/sysctl.h> + +#include <linux/sys_info.h> + +static const char * const si_names[] = { + [ilog2(SYS_INFO_TASKS)] = "tasks", + [ilog2(SYS_INFO_MEM)] = "mem", + [ilog2(SYS_INFO_TIMERS)] = "timers", + [ilog2(SYS_INFO_LOCKS)] = "locks", + [ilog2(SYS_INFO_FTRACE)] = "ftrace", + [ilog2(SYS_INFO_PANIC_CONSOLE_REPLAY)] = "", + [ilog2(SYS_INFO_ALL_BT)] = "all_bt", + [ilog2(SYS_INFO_BLOCKED_TASKS)] = "blocked_tasks", +}; + +/* + * Default kernel sys_info mask. + * If a kernel module calls sys_info() with "parameter == 0", then + * this mask will be used. + */ +static unsigned long kernel_si_mask; + +/* Expecting string like "xxx_sys_info=tasks,mem,timers,locks,ftrace,..." */ +unsigned long sys_info_parse_param(char *str) +{ + unsigned long si_bits = 0; + char *s, *name; + int i; + + s = str; + while ((name = strsep(&s, ",")) && *name) { + i = match_string(si_names, ARRAY_SIZE(si_names), name); + if (i >= 0) + __set_bit(i, &si_bits); + } + + return si_bits; +} + +#ifdef CONFIG_SYSCTL + +static int sys_info_write_handler(const struct ctl_table *table, + void *buffer, size_t *lenp, loff_t *ppos, + unsigned long *si_bits_global) +{ + unsigned long si_bits; + int ret; + + ret = proc_dostring(table, 1, buffer, lenp, ppos); + if (ret) + return ret; + + si_bits = sys_info_parse_param(table->data); + + /* The access to the global value is not synchronized. */ + WRITE_ONCE(*si_bits_global, si_bits); + + return 0; +} + +static int sys_info_read_handler(const struct ctl_table *table, + void *buffer, size_t *lenp, loff_t *ppos, + unsigned long *si_bits_global) +{ + unsigned long si_bits; + unsigned int len = 0; + char *delim = ""; + unsigned int i; + + /* The access to the global value is not synchronized. */ + si_bits = READ_ONCE(*si_bits_global); + + for_each_set_bit(i, &si_bits, ARRAY_SIZE(si_names)) { + if (*si_names[i]) { + len += scnprintf(table->data + len, table->maxlen - len, + "%s%s", delim, si_names[i]); + delim = ","; + } + } + + return proc_dostring(table, 0, buffer, lenp, ppos); +} + +int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write, + void *buffer, size_t *lenp, + loff_t *ppos) +{ + struct ctl_table table; + unsigned int i; + size_t maxlen; + + maxlen = 0; + for (i = 0; i < ARRAY_SIZE(si_names); i++) + maxlen += strlen(si_names[i]) + 1; + + char *names __free(kfree) = kzalloc(maxlen, GFP_KERNEL); + if (!names) + return -ENOMEM; + + table = *ro_table; + table.data = names; + table.maxlen = maxlen; + + if (write) + return sys_info_write_handler(&table, buffer, lenp, ppos, ro_table->data); + else + return sys_info_read_handler(&table, buffer, lenp, ppos, ro_table->data); +} + +static const struct ctl_table sys_info_sysctls[] = { + { + .procname = "kernel_sys_info", + .data = &kernel_si_mask, + .maxlen = sizeof(kernel_si_mask), + .mode = 0644, + .proc_handler = sysctl_sys_info_handler, + }, +}; + +static int __init sys_info_sysctl_init(void) +{ + register_sysctl_init("kernel", sys_info_sysctls); + return 0; +} +subsys_initcall(sys_info_sysctl_init); +#endif + +static void __sys_info(unsigned long si_mask) +{ + if (si_mask & SYS_INFO_TASKS) + show_state(); + + if (si_mask & SYS_INFO_MEM) + show_mem(); + + if (si_mask & SYS_INFO_TIMERS) + sysrq_timer_list_show(); + + if (si_mask & SYS_INFO_LOCKS) + debug_show_all_locks(); + + if (si_mask & SYS_INFO_FTRACE) + ftrace_dump(DUMP_ALL); + + if (si_mask & SYS_INFO_ALL_BT) + trigger_all_cpu_backtrace(); + + if (si_mask & SYS_INFO_BLOCKED_TASKS) + show_state_filter(TASK_UNINTERRUPTIBLE); +} + +void sys_info(unsigned long si_mask) +{ + __sys_info(si_mask ? : kernel_si_mask); +} |