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. --- fs/proc/proc_tty.c | 177 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+) create mode 100644 fs/proc/proc_tty.c (limited to 'fs/proc/proc_tty.c') diff --git a/fs/proc/proc_tty.c b/fs/proc/proc_tty.c new file mode 100644 index 000000000..5c6a5ceab --- /dev/null +++ b/fs/proc/proc_tty.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * proc_tty.c -- handles /proc/tty + * + * Copyright 1997, Theodore Ts'o + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +/* + * The /proc/tty directory inodes... + */ +static struct proc_dir_entry *proc_tty_driver; + +/* + * This is the handler for /proc/tty/drivers + */ +static void show_tty_range(struct seq_file *m, struct tty_driver *p, + dev_t from, int num) +{ + seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown"); + seq_printf(m, "/dev/%-8s ", p->name); + if (p->num > 1) { + seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from), + MINOR(from) + num - 1); + } else { + seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from)); + } + switch (p->type) { + case TTY_DRIVER_TYPE_SYSTEM: + seq_puts(m, "system"); + if (p->subtype == SYSTEM_TYPE_TTY) + seq_puts(m, ":/dev/tty"); + else if (p->subtype == SYSTEM_TYPE_SYSCONS) + seq_puts(m, ":console"); + else if (p->subtype == SYSTEM_TYPE_CONSOLE) + seq_puts(m, ":vtmaster"); + break; + case TTY_DRIVER_TYPE_CONSOLE: + seq_puts(m, "console"); + break; + case TTY_DRIVER_TYPE_SERIAL: + seq_puts(m, "serial"); + break; + case TTY_DRIVER_TYPE_PTY: + if (p->subtype == PTY_TYPE_MASTER) + seq_puts(m, "pty:master"); + else if (p->subtype == PTY_TYPE_SLAVE) + seq_puts(m, "pty:slave"); + else + seq_puts(m, "pty"); + break; + default: + seq_printf(m, "type:%d.%d", p->type, p->subtype); + } + seq_putc(m, '\n'); +} + +static int show_tty_driver(struct seq_file *m, void *v) +{ + struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers); + dev_t from = MKDEV(p->major, p->minor_start); + dev_t to = from + p->num; + + if (&p->tty_drivers == tty_drivers.next) { + /* pseudo-drivers first */ + seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty"); + seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0); + seq_puts(m, "system:/dev/tty\n"); + seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console"); + seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1); + seq_puts(m, "system:console\n"); +#ifdef CONFIG_UNIX98_PTYS + seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx"); + seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2); + seq_puts(m, "system\n"); +#endif +#ifdef CONFIG_VT + seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0"); + seq_printf(m, "%3d %7d ", TTY_MAJOR, 0); + seq_puts(m, "system:vtmaster\n"); +#endif + } + + while (MAJOR(from) < MAJOR(to)) { + dev_t next = MKDEV(MAJOR(from)+1, 0); + show_tty_range(m, p, from, next - from); + from = next; + } + if (from != to) + show_tty_range(m, p, from, to - from); + return 0; +} + +/* iterator */ +static void *t_start(struct seq_file *m, loff_t *pos) +{ + mutex_lock(&tty_mutex); + return seq_list_start(&tty_drivers, *pos); +} + +static void *t_next(struct seq_file *m, void *v, loff_t *pos) +{ + return seq_list_next(v, &tty_drivers, pos); +} + +static void t_stop(struct seq_file *m, void *v) +{ + mutex_unlock(&tty_mutex); +} + +static const struct seq_operations tty_drivers_op = { + .start = t_start, + .next = t_next, + .stop = t_stop, + .show = show_tty_driver +}; + +/* + * This function is called by tty_register_driver() to handle + * registering the driver's /proc handler into /proc/tty/driver/ + */ +void proc_tty_register_driver(struct tty_driver *driver) +{ + struct proc_dir_entry *ent; + + if (!driver->driver_name || driver->proc_entry || + !driver->ops->proc_show) + return; + + ent = proc_create_single_data(driver->driver_name, 0, proc_tty_driver, + driver->ops->proc_show, driver); + driver->proc_entry = ent; +} + +/* + * This function is called by tty_unregister_driver() + */ +void proc_tty_unregister_driver(struct tty_driver *driver) +{ + struct proc_dir_entry *ent; + + ent = driver->proc_entry; + if (!ent) + return; + + remove_proc_entry(ent->name, proc_tty_driver); + + driver->proc_entry = NULL; +} + +/* + * Called by proc_root_init() to initialize the /proc/tty subtree + */ +void __init proc_tty_init(void) +{ + if (!proc_mkdir("tty", NULL)) + return; + proc_mkdir("tty/ldisc", NULL); /* Preserved: it's userspace visible */ + /* + * /proc/tty/driver/serial reveals the exact character counts for + * serial links which is just too easy to abuse for inferring + * password lengths and inter-keystroke timings during password + * entry. + */ + proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL); + proc_create_seq("tty/ldiscs", 0, NULL, &tty_ldiscs_seq_ops); + proc_create_seq("tty/drivers", 0, NULL, &tty_drivers_op); +} -- cgit v1.3.1