linux/kernel/time/timer_list.c
Alexey Dobriyan 9d65cb4a17 Fix race between cat /proc/*/wchan and rmmod et al
kallsyms_lookup() can go iterating over modules list unprotected which is OK
for emergency situations (oops), but not OK for regular stuff like
/proc/*/wchan.

Introduce lookup_symbol_name()/lookup_module_symbol_name() which copy symbol
name into caller-supplied buffer or return -ERANGE.  All copying is done with
module_mutex held, so...

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:08 -07:00

283 lines
6.7 KiB
C

/*
* kernel/time/timer_list.c
*
* List pending timers
*
* Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/proc_fs.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/kallsyms.h>
#include <linux/tick.h>
#include <asm/uaccess.h>
typedef void (*print_fn_t)(struct seq_file *m, unsigned int *classes);
DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
/*
* This allows printing both to /proc/timer_list and
* to the console (on SysRq-Q):
*/
#define SEQ_printf(m, x...) \
do { \
if (m) \
seq_printf(m, x); \
else \
printk(x); \
} while (0)
static void print_name_offset(struct seq_file *m, void *sym)
{
char symname[KSYM_NAME_LEN+1];
if (lookup_symbol_name((unsigned long)sym, symname) < 0)
SEQ_printf(m, "<%p>", sym);
else
SEQ_printf(m, "%s", symname);
}
static void
print_timer(struct seq_file *m, struct hrtimer *timer, int idx, u64 now)
{
#ifdef CONFIG_TIMER_STATS
char tmp[TASK_COMM_LEN + 1];
#endif
SEQ_printf(m, " #%d: ", idx);
print_name_offset(m, timer);
SEQ_printf(m, ", ");
print_name_offset(m, timer->function);
SEQ_printf(m, ", S:%02lx", timer->state);
#ifdef CONFIG_TIMER_STATS
SEQ_printf(m, ", ");
print_name_offset(m, timer->start_site);
memcpy(tmp, timer->start_comm, TASK_COMM_LEN);
tmp[TASK_COMM_LEN] = 0;
SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
#endif
SEQ_printf(m, "\n");
SEQ_printf(m, " # expires at %Ld nsecs [in %Ld nsecs]\n",
(unsigned long long)ktime_to_ns(timer->expires),
(unsigned long long)(ktime_to_ns(timer->expires) - now));
}
static void
print_active_timers(struct seq_file *m, struct hrtimer_clock_base *base,
u64 now)
{
struct hrtimer *timer, tmp;
unsigned long next = 0, i;
struct rb_node *curr;
unsigned long flags;
next_one:
i = 0;
spin_lock_irqsave(&base->cpu_base->lock, flags);
curr = base->first;
/*
* Crude but we have to do this O(N*N) thing, because
* we have to unlock the base when printing:
*/
while (curr && i < next) {
curr = rb_next(curr);
i++;
}
if (curr) {
timer = rb_entry(curr, struct hrtimer, node);
tmp = *timer;
spin_unlock_irqrestore(&base->cpu_base->lock, flags);
print_timer(m, &tmp, i, now);
next++;
goto next_one;
}
spin_unlock_irqrestore(&base->cpu_base->lock, flags);
}
static void
print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
{
SEQ_printf(m, " .index: %d\n",
base->index);
SEQ_printf(m, " .resolution: %Ld nsecs\n",
(unsigned long long)ktime_to_ns(base->resolution));
SEQ_printf(m, " .get_time: ");
print_name_offset(m, base->get_time);
SEQ_printf(m, "\n");
#ifdef CONFIG_HIGH_RES_TIMERS
SEQ_printf(m, " .offset: %Ld nsecs\n",
ktime_to_ns(base->offset));
#endif
SEQ_printf(m, "active timers:\n");
print_active_timers(m, base, now);
}
static void print_cpu(struct seq_file *m, int cpu, u64 now)
{
struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
int i;
SEQ_printf(m, "\ncpu: %d\n", cpu);
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
SEQ_printf(m, " clock %d:\n", i);
print_base(m, cpu_base->clock_base + i, now);
}
#define P(x) \
SEQ_printf(m, " .%-15s: %Ld\n", #x, (u64)(cpu_base->x))
#define P_ns(x) \
SEQ_printf(m, " .%-15s: %Ld nsecs\n", #x, \
(u64)(ktime_to_ns(cpu_base->x)))
#ifdef CONFIG_HIGH_RES_TIMERS
P_ns(expires_next);
P(hres_active);
P(nr_events);
#endif
#undef P
#undef P_ns
#ifdef CONFIG_TICK_ONESHOT
# define P(x) \
SEQ_printf(m, " .%-15s: %Ld\n", #x, (u64)(ts->x))
# define P_ns(x) \
SEQ_printf(m, " .%-15s: %Ld nsecs\n", #x, \
(u64)(ktime_to_ns(ts->x)))
{
struct tick_sched *ts = tick_get_tick_sched(cpu);
P(nohz_mode);
P_ns(idle_tick);
P(tick_stopped);
P(idle_jiffies);
P(idle_calls);
P(idle_sleeps);
P_ns(idle_entrytime);
P_ns(idle_sleeptime);
P(last_jiffies);
P(next_jiffies);
P_ns(idle_expires);
SEQ_printf(m, "jiffies: %Ld\n", (u64)jiffies);
}
#endif
#undef P
#undef P_ns
}
#ifdef CONFIG_GENERIC_CLOCKEVENTS
static void
print_tickdevice(struct seq_file *m, struct tick_device *td)
{
struct clock_event_device *dev = td->evtdev;
SEQ_printf(m, "\nTick Device: mode: %d\n", td->mode);
SEQ_printf(m, "Clock Event Device: ");
if (!dev) {
SEQ_printf(m, "<NULL>\n");
return;
}
SEQ_printf(m, "%s\n", dev->name);
SEQ_printf(m, " max_delta_ns: %lu\n", dev->max_delta_ns);
SEQ_printf(m, " min_delta_ns: %lu\n", dev->min_delta_ns);
SEQ_printf(m, " mult: %lu\n", dev->mult);
SEQ_printf(m, " shift: %d\n", dev->shift);
SEQ_printf(m, " mode: %d\n", dev->mode);
SEQ_printf(m, " next_event: %Ld nsecs\n",
(unsigned long long) ktime_to_ns(dev->next_event));
SEQ_printf(m, " set_next_event: ");
print_name_offset(m, dev->set_next_event);
SEQ_printf(m, "\n");
SEQ_printf(m, " set_mode: ");
print_name_offset(m, dev->set_mode);
SEQ_printf(m, "\n");
SEQ_printf(m, " event_handler: ");
print_name_offset(m, dev->event_handler);
SEQ_printf(m, "\n");
}
static void timer_list_show_tickdevices(struct seq_file *m)
{
int cpu;
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
print_tickdevice(m, tick_get_broadcast_device());
SEQ_printf(m, "tick_broadcast_mask: %08lx\n",
tick_get_broadcast_mask()->bits[0]);
#ifdef CONFIG_TICK_ONESHOT
SEQ_printf(m, "tick_broadcast_oneshot_mask: %08lx\n",
tick_get_broadcast_oneshot_mask()->bits[0]);
#endif
SEQ_printf(m, "\n");
#endif
for_each_online_cpu(cpu)
print_tickdevice(m, tick_get_device(cpu));
SEQ_printf(m, "\n");
}
#else
static void timer_list_show_tickdevices(struct seq_file *m) { }
#endif
static int timer_list_show(struct seq_file *m, void *v)
{
u64 now = ktime_to_ns(ktime_get());
int cpu;
SEQ_printf(m, "Timer List Version: v0.3\n");
SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
for_each_online_cpu(cpu)
print_cpu(m, cpu, now);
SEQ_printf(m, "\n");
timer_list_show_tickdevices(m);
return 0;
}
void sysrq_timer_list_show(void)
{
timer_list_show(NULL, NULL);
}
static int timer_list_open(struct inode *inode, struct file *filp)
{
return single_open(filp, timer_list_show, NULL);
}
static struct file_operations timer_list_fops = {
.open = timer_list_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init init_timer_list_procfs(void)
{
struct proc_dir_entry *pe;
pe = create_proc_entry("timer_list", 0644, NULL);
if (!pe)
return -ENOMEM;
pe->proc_fops = &timer_list_fops;
return 0;
}
__initcall(init_timer_list_procfs);