From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- lib/sys_info.c | 166 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 lib/sys_info.c (limited to 'lib/sys_info.c') diff --git a/lib/sys_info.c b/lib/sys_info.c new file mode 100644 index 000000000..f32a06ec9 --- /dev/null +++ b/lib/sys_info.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +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); +} -- cgit v1.3.1